<PAGE>   1
                                                                 EXHIBIT 10.1.5



                                                              EXECUTION COPY


                                  WAIVER NO. 4
                                       TO
                                CREDIT AGREEMENT
                                       AND
                              OTHER LOAN DOCUMENTS


                  THIS WAIVER NO. 4 TO CREDIT AGREEMENT AND OTHER LOAN DOCUMENTS
("Agreement") is being executed and delivered as of June 12, 1998 by and among
Code-Alarm, Inc., a Michigan corporation (the "Borrower"), the other "Credit
Parties" from time to time party to the Credit Agreement referred to below
(together with the Borrower, collectively, the "Credit Parties"), the financial
institutions from time to time party to such Credit Agreement (collectively, the
"Lenders", and each individually, a "Lender"), and General Electric Capital
Corporation, in its individual capacity, and as the "Agent" for the Lenders (the
"Agent"). Undefined capitalized terms which are used herein shall have the
meanings ascribed to such terms in the Credit Agreement.

                              W I T N E S S E T H:

                  WHEREAS, the Borrower, the other Credit Parties, the Lenders
and the Agent are parties to that certain Credit Agreement dated as of October
24, 1997, as heretofore amended (the "Credit Agreement"), pursuant to which the
Lenders have agreed to provide, subject to the terms and conditions contained
therein, certain loans and other financial accommodations to the Borrower;

                  WHEREAS, the Credit Agreement and Litigation L/C Agreement
provide, among other things, that (i) if the Bond and the Litigation L/C are
drawn, the Borrower's reimbursement obligations to the Lenders with respect to
the Litigation L/C would constitute Term Loan C or, alternatively, (ii) if the
DEI Litigation is settled or a Final Judgment is otherwise entered and payable
by the Borrower, then, upon request by the Borrower, the Lenders would directly
fund Term Loan C in an amount sufficient to satisfy such settlement or other
Final Judgment;

                  WHEREAS, the Borrower has entered into a settlement agreement
with Directed Electronics, Inc. ("Directed") with respect to the DEI Litigation,
a true and complete copy of which is attached as Exhibit A hereto (the
"Settlement Agreement"), pursuant to which, among other things, the Borrower is
obligated to pay $10,000,000 to Directed (the "Settlement Amount"),
$9,341,030.00 of which through a drawing by Directed of the Bond (the "Drawn
Portion") and the remaining $658,970.00 of which in cash directly to Directed
(the "Funded Portion"); and



<PAGE>   2



                  WHEREAS, the Borrower has requested that the Lenders and
Agent, and subject to the terms and conditions of this Agreement, the Lenders
and Agent are willing to (i) permit the Borrower to utilize the Term Loan C
Commitment to pay the entire Settlement Amount in accordance with the payment
terms of the Settlement Agreement notwithstanding the provisions of the Credit
Agreement and Litigation L/C Agreement which currently permit the Borrower to
pay settlement consideration with respect to the DEI Litigation through a draw
of the Bond and Litigation L/C or through a direct funding under the Term Loan C
Commitment, but not through a combination of both means as is required under the
Settlement Agreement and (ii) waive certain other provisions of the Credit
Agreement.

                  NOW, THEREFORE, in consideration of the foregoing premises,
the terms and conditions stated herein and other valuable consideration, the
receipt and sufficiency of which are hereby acknowledged by the Borrower, the
Lenders, the Agent, such parties hereby agree as follows:

                  1. Waiver. Subject to Paragraph 3 of this Agreement and
effective as of the date of this Agreement, each of the Lenders and the Agent
hereby waives:

                  (a) the requirement set forth in Section 1.1(d)(iii) of the
         Credit Agreement and Section 1.1(c) of the Litigation L/C Agreement
         that, in order for the Borrower to obtain a direct loan pursuant to the
         Term Loan C Commitment to fund the Funded Portion, either no Litigation
         L/C Obligations shall have been then previously incurred, or the
         Litigation L/C shall have been then previously terminated, provided,
         that, for all purposes under the Credit Agreement, Litigation L/C
         Agreement and the other Loan Documents, (i) the Lenders shall be deemed
         to have funded Term Loan C for the account of the Borrower in an
         aggregate original principal amount equal to the Settlement Amount upon
         the drawing of the Litigation L/C in an amount equal to the Drawn
         Portion and the Lenders' funding of the Funded Portion otherwise in
         accordance with the terms and conditions of such sections of the Credit
         Agreement and Litigation L/C Agreement, (ii) from and after such
         drawing and funding, the Lenders shall have no further obligation or
         commitment to provide Loans or Letters of Credit with respect to the
         Term Loan C Commitment or Term Loan B Commitment and (iii) Term Loan C
         shall be evidenced by the Term C Note, governed by and repayable in
         accordance with the terms and conditions of the Credit Agreement, the
         Litigation L/C Agreement and the other Loan Documents, secured by the
         Collateral pursuant to the Litigation Collateral Documents, and
         guaranteed pursuant to the Litigation Guaranty;

                  (b) the requirement set forth in Section 1.1(d)(iii) of the
         Credit Agreement that a Notice of Term C Advance be given no later than
         11:00 a.m. (Chicago time) on a date which is three (3) Business Days
         prior to the Term Loan C Funding Date, provided, that, (i) this
         Agreement shall constitute a Notice of Term C Advance (as more
         particularly set forth in Paragraph 2 below) and (ii) Term Loan C shall
         initially be an Index Rate Loan (which may be later converted by the
         Borrower to a LIBOR Loan pursuant to Section 1.5(e) of the Credit
         Agreement); and

                                       -2-

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                  (c) the representations and warranties set forth in Section
         3.11 with respect to extensions by the Borrower and the IRS of the
         IRS's continuing examination of the Borrower's tax returns for 1994.

                  2. Request for Term C Advance. The Borrower hereby irrevocable
requests the Term Lenders to directly advance the Funded Portion to Directed
pursuant to the wire transfer instructions attached as Exhibit B hereto on the
first Business Day after the date hereof on which all of the conditions
precedent set forth in Paragraph 3 of this Agreement, Section 2.3(II) of the
Credit Agreement and Section 2.4 of the Credit Agreement, have been satisfied
(other than the condition set forth in Section 2.3(II)(e)); provided, however,
that if such conditions are satisfied after 11:00 a.m. (Chicago time) on a
Business Day, such funding may be made on the next succeeding Business Day.
Notwithstanding anything in the Loan Documents to the contrary, this Agreement
hereby constitutes the Borrower's Notice of Term C Advance, and the date on
which Term Loan C is made pursuant to this Agreement shall constitute the Term
Loan C Funding Date.

                  3. Effectiveness of this Agreement; Conditions Precedent. The
provisions of Paragraph 1 shall be deemed to have become effective as of the
date of this Agreement, but such effectiveness shall be expressly conditioned
upon the Agent's receipt on or before June 30, 1998 of each of the following:

                  (a) an originally-executed counterpart of this Agreement
executed by a duly authorized officer of the Borrower, each other Credit Party,
and each of the Requisite Lenders;

                  (b) originally-executed counterparts to a Reaffirmation of
Guaranties duly executed by the Pegasus Funds substantially in the form attached
hereto;

                  (c) copies of court orders and other evidence satisfactory to
the Agent indicating that the Lower Court has approved the Settlement Agreement
and the payment of the Drawn Portion to Directed pursuant to the terms and
conditions of the Settlement Agreement;

                  (d) evidence satisfactory to the Agent that the Drawn Portion
has been paid to Directed pursuant to the terms and conditions of the Settlement
Agreement; and

                  (e) an originally-executed certificate of Borrower's chief
financial officer with respect to the anti-dilution adjustments to the GECC
Warrants resulting from the issuance of the additional "Litigation Warrants" (as
defined in the Series A Preferred Stock Documents) to be issued by Borrower to
the Pegasus Funds simultaneously with the Lenders' funding of the Funded Portion
of Term Loan C as contemplated by this Agreement, together with certified copies
of the fully-executed Litigation Warrants so issued or to be issued.

                  4. Representations, Warranties and Covenants. (a) The Borrower
and each other Credit Party hereby represents and warrants that this Agreement
constitutes the legal, valid and 



                                      -3-
<PAGE>   4

binding obligation of the Borrower and such other Credit Party enforceable
against the Borrower and each other Credit Party in accordance with its terms.

                  (b) The Borrower and each other Credit Party hereby represents
and warrants that its execution and delivery of this Agreement, and its
performance hereafter of the Credit Agreement as modified by this Agreement,
have been duly authorized by all necessary corporate action, do not violate any
provision of its articles of incorporation, bylaws or other charter documents,
will not violate any law, regulation, court order or writ applicable to it, will
not require the approval or consent of any governmental agency, and (except as
provided in this Agreement) do not require the approval or consent of any third
party under the terms of any contract or agreement to which the Borrower, any
other Credit Party, Parent or any Subsidiary of the Borrower or any other Credit
Party is bound.

                  (c) The Borrower hereby represents and warrants that, as of
the date hereof, and on the Term Loan C Funding Date both before and after
giving effect to the making and application of Term Loan C pursuant to the terms
of this Agreement, (i) no Default or Event of Default has occurred and is
continuing or will have occurred and be continuing, (ii) all of the
representations and warranties of the Borrower and each other Credit Party
contained in the Credit Agreement (other than representations and warranties
which, in accordance with their express terms, are made only as of a specified
date) are, and will be, true and correct, (iii) the Borrower is and, to the best
of the Borrower's knowledge Directed is, in full compliance with the terms and
conditions of the Settlement Agreement, (iv) all representations and warranties
made by the Borrower, and, to the best of the Borrower's knowledge, all of the
representations and warranties of Directed, to the extent set forth in the
Settlement Agreement, are true and complete in all respects, and (v) all of the
conditions set forth in Sections 2.3(II) and 2.4 of the Credit Agreement, have
been satisfied (other than the condition set forth in Section 2.3(II)(e) of the
Credit Agreement).

                  (d) The Borrower hereby covenants to (i) provide the Agent,
promptly upon its filing or receipt thereof, true and complete copies of all
pleadings and orders relating to any of the dismissals described in Sections 3
or 12 of the Settlement Agreement, or any of the satisfactions described in
Section 4 of the Settlement Agreement, (ii) provide the Agent, promptly upon its
obtaining knowledge thereof, notice of the Borrower's or Directed's breach or
other noncompliance, or alleged breach or noncompliance, with any provision,
representation or warranty set forth in the Settlement Agreement and (iii) not
to amend, waive or otherwise modify any term or provision of the Settlement
Agreement without the prior written consent of the Requisite Lenders.

                  (e) The Borrower, the Lenders and the Agent hereby agree that,
notwithstanding anything in the Loan Documents to the contrary, any material
breach by the Borrower or Directed of any representation, warranty, term or
condition of the Settlement Agreement shall thereupon constitute an immediate
Event of Default under and as used in the Credit Agreement.

                  6. Reference to and Effect on Loan Documents. Each of the Loan
Documents shall remain in full force and effect and is hereby ratified and
confirmed. Without limiting the 





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<PAGE>   5

foregoing, the Borrower hereby reaffirms the Borrower's grant to the Agent of
each of the Agent's Liens, on behalf of itself and the Lenders, pursuant to the
Collateral Documents and the Litigation Collateral Documents. Neither the
execution, delivery nor effectiveness of this Agreement shall operate as a
waiver of any right, power or remedy of the Agent or any Lender of any Default
or Event of Default under the Credit Agreement, all of which the Agent and the
Lenders hereby expressly reserve. The Borrower, each other Credit Party, the
Lenders and the Agent agree and acknowledge that this Agreement constitutes a
"Loan Document" under and as defined in the Credit Agreement.

                  7. Reaffirmation. Each of the Borrower and the other Credit
Parties hereby (a) ratifies and reaffirms all of its payment and performance
obligations, contingent or otherwise, under each Loan Document to which it is a
party, (b) agrees and acknowledges that such ratification and reaffirmation is
not a condition to the continued effectiveness of such Loan Documents and (c)
agrees that neither such ratification and reaffirmation, nor the Agent's and the
Lenders' solicitation of such ratification and reaffirmation, constitutes a
course of dealing giving rise to any obligation or condition requiring a
ratification or reaffirmation of the Borrower's or the other Credit Parties'
obligations under the Loan Documents with respect to any subsequent
modifications to the Credit Agreement or other Loan Documents.

                  8. Governing Law. This Agreement shall be governed by and
construed in accordance with the laws and decisions of the State of Illinois
(including S.H.A. 735 ILCS 105/5-1, et. seq., but without giving effect to any
other conflicts of law provisions).

                  9. Agent's Expenses. The Borrower hereby agrees to promptly
reimburse the Agent for all of the reasonable out-of-pocket expenses, including,
without limitation, attorneys' and paralegals' fees, it has heretofore or
hereafter incurred or incurs in connection with the preparation, negotiation and
execution of this Agreement.

                  10. Counterparts. This Agreement may be executed in
counterparts, each of which shall be an original and all of which together shall
constitute one and the same agreement among the parties.

                                     * * * *


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                  IN WITNESS WHEREOF, this Agreement has been duly executed as
of the day and year first above written.

                                                     CODE-ALARM, INC.



                                       By:
                                           -----------------------------------
                                            Name:   Craig S. Camalo
                                                 -----------------------------
                                            Title:   Vice President
                                                  ----------------------------


                                            GENERAL ELECTRIC CAPITAL
                                            CORPORATION, as Agent and Lender,
                                            and as holder of the GECC Warrants



                                       By:
                                           -----------------------------------
                                            Name:   Catharine L. Midkiff
                                                 -----------------------------
                                            Title:   Duly Authorized Signatory
                                                  ----------------------------


                                       TESSCO GROUP, INC.



                                       By:
                                           -----------------------------------
                                            Name:   Craig S. Camalo
                                                 -----------------------------
                                            Title:   Secretary
                                                  ----------------------------


                                       CHAPMAN SECURITY SYSTEMS, INC.



                                       By:
                                           -----------------------------------
                                            Name:   Craig S. Camalo
                                                 -----------------------------
                                            Title:   Secretary
                                                  ----------------------------

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<PAGE>   7



                                       INTERCEPT SYSTEMS, INC.



                                       By:
                                          -----------------------------
                                            Name:   Craig S. Camalo
                                                 ----------------------
                                            Title:   Secretary
                                                  ---------------------

                                       ANES, INC.



                                       By:
                                          -----------------------------
                                            Name:   Craig S. Camalo
                                                 ----------------------
                                            Title:   Secretary
                                                  ---------------------





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<PAGE>   8



                         REAFFIRMATION OF GUARANTIES

                  Reference is hereby made to (i) that certain Limited
Supplemental Guaranty dated as of October 24, 1997 (the "Supplemental Guaranty")
among Pegasus Partners, L.P., a Delaware limited partnership, and Pegasus
Related Partners, L.P., a Delaware limited partnership (collectively, the
"Guarantors"), and General Electric Capital Corporation, a New York corporation,
individually and as agent (the "Agent"), (ii) that certain Limited Litigation
Guaranty dated as of October 24, 1997 (the "Litigation Guaranty") among the
Guarantors and the Agent, (iii) that certain Credit Agreement dated as of
October 24, 1997, as heretofore amended (the "Credit Agreement"), among
Code-Alarm, Inc., a Michigan corporation (the "Borrower"), certain other "Credit
Parties" referred to and as defined therein (the "Credit Parties"), certain
"Lenders" from time to time party thereto (the "Lenders"), and the Agent, and
(iv) that certain Waiver No. 4 to Credit Agreement and Other Loan Documents of
even date herewith (the "Waiver") among the Borrower, the Credit Parties, the
Lenders and the Agent.

                  Each of the Guarantors hereby:

                  (a) acknowledges having received and reviewed a copy of the
Waiver and hereby consent to its terms and provisions;

                  (b) subject to clause (c) below, ratifies and reaffirms all of
its payment and performance obligations, contingent or otherwise, under the
Supplemental Guaranty and the Litigation Guaranty (collectively, the
"Guaranties");

                  (c) confirms and agrees that, notwithstanding anything in the
Litigation Guaranty or any other Loan Document to the contrary, upon the funding
by the Lenders of the "Funded Portion" pursuant to and as defined in the Waiver,
the "Limitation Amount" (as referred to and as defined in the Litigation
Guaranty) shall equal $10,000,000 and the "Termination Date" (as referred to and
used in the Litigation Guaranty) shall be the date on which Term Loan C is
repaid in full (subject to the proviso at the end of the second to last sentence
of Section 2.1 of the Litigation Guaranty);

                  (d) confirms that it has received additional Litigation
Warrants in sufficient form and amount, together with all related opinions,
certificates, documents and instruments, as may be required by the Litigation
Guaranty and by that certain Unit Purchase Agreement dated as of October 24,
1997 among the Borrower and the Guarantors;

                  (e) certifies that together herewith it has delivered a
calculation of the Net Assets and Unpaid Capital Obligations of each Guarantor
as of the date hereof, and a calculation of the Aggregate Net Capital and
Aggregate Portfolio Cash Flow as of the date hereof (in each case as defined in
the Litigation Guaranty);

                  (f) confirms that each of the representations and warranties
set forth in Section 4 of the Litigation Guaranty are true and correct as of the
date hereof; and




<PAGE>   9



                  (g) agrees and acknowledges that each of the Effectiveness
Conditions have been previously satisfied and the Effective Date has previously
occurred (as such capitalized terms are defined in the Litigation Guaranty).

                  IN WITNESS WHEREOF, this instrument has been executed and
delivered as of this 12th day of June, 1998.



PEGASUS PARTNERS, L.P.                      PEGASUS RELATED PARTNERS, L.P.
By: PEGASUS INVESTORS, L.P.,                   By: PEGASUS INVESTORS, L.P.,
      as Managing General Partner                 as Managing General Partner
By: PEGASUS INVESTORS GP, INC.,                By: PEGASUS INVESTORS GP, INC.,
      as General Partner                    as General Partner



By:                                            By:
   ------------------------------                 ------------------------------
   Name:  Richard Cion                            Name:  Richard Cion
          -----------------------                       ------------------------
   Title: Vice President                          Title: Vice President
          -----------------------                       ------------------------



<PAGE>   10



                                    EXHIBIT A
                                       to
                        Waiver No. 4 to Credit Agreement
                            and Other Loan Documents
                            Dated as of June 12, 1998



                              Settlement Agreement


                                    Attached.


<PAGE>   11


                                    EXHIBIT B
                                       to
                        Waiver No. 4 to Credit Agreement
                            and Other Loan Documents
                            Dated as of June 12, 1998


                           Wire Transfer Instructions


                             Wells Fargo Bank, N.A.
                         San Francisco, California 94163
                             Fedwire ABA: 121000248
                               For the account of:
                           Directed Electronics, Inc.
                             Vista, California 92083
                             Account No.: 4159294156