<PAGE>

                                                                     Exhibit 4.2

                 WARRANT

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAWS, AND MAY
NOT BE PLEDGED, SOLD, OFFERED FOR SALE, TRANSFERRED, OR OTHERWISE DISPOSED OF IN
THE ABSENCE OF REGISTRATION UNDER OR EXEMPTION FROM SUCH ACT AND ALL APPLICABLE
STATE SECURITIES LAWS. THE COMPANY MAY REQUIRE AN OPINION OF COUNSEL REASONABLY
ACCEPTABLE TO IT THAT A PROPOSED TRANSFER OR SALE IS IN COMPLIANCE WITH THE ACT,
EXCEPT THAT NO SUCH OPINION SHALL BE REQUIRED FOR TRANSFERS OR SALES PURSUANT TO
REGISTRATION UNDER THE ACT.

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF ARE SUBJECT TO THE
TERMS AND PROVISIONS OF A VALUE PARTICIPATION AGREEMENT (AS SUPPLEMENTED,
MODIFIED, AMENDED, OR RESTATED FROM TIME TO TIME, THE "AGREEMENT") DATED MARCH
23, 2000 BETWEEN FORD MOTOR COMPANY ("FORD") AND AMERIGON INCORPORATED (THE
"COMPANY") A COPY OF THE AGREEMENT IS AVAILABLE AT THE EXECUTIVE OFFICES OF THE
COMPANY.

82,197 Shares of Class A
Common Stock
of the Company                                                    Warrant No. 28

         WARRANT TO PURCHASE CLASS A COMMON STOCK OF
              AMERIGON INCORPORATED

  This is to certify that, in consideration of ten dollars ($10.00) and
other valuable consideration, which is hereby acknowledged as received, Ford
Motor Company, its successors and registered assigns, is entitled to exercise
this Warrant to purchase Eighty Two Thousand One Hundred Ninety Seven (82,197)
shares of the Class A Common Stock of Amerigon Incorporated, a California
corporation (the "Company"), as the same shall be adjusted from time to time
pursuant to the provisions of the Agreement, at any time in accordance with the
terms of the Agreement, at a price equal to $2.75 per share and to exercise the
other rights, powers, and privileges hereinafter provided, all on the terms and
subject to the conditions specified in this Warrant and in the Agreement. This
Warrant shall expire on March 23, 2007.

  This Warrant is issued under, and the rights represented hereby are
subject to the terms and provisions contained in the Agreement, to all terms and
provisions of which the
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registered holder of this Warrant, by acceptance of this Warrant, assents.
Reference is hereby made to the Agreement for a more complete statement of the
rights and limitations of rights of the registered holder of this Warrant and
the rights and duties of the Company under this Warrant. Capitalized terms used
but not defined herein have the meanings set forth in the Agreement. A copy of
the Agreement is on file at the office of the Company.

  IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed.

Dated as of March 27, 2000.

                   AMERIGON INCORPORATED


                   By: /s/ Richard Weisbart
                                             ---------------------------------
                     Its: PRESIDENT & CEO
                                                  ----------------------------


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<PAGE>

               ASSIGNMENT FORM

  FOR VALUE RECEIVED the undersigned registered owner of this Warrant hereby
sells, assigns and transfers unto the Assignee named below all of the rights of
the undersigned under this Warrant, with respect to the number of shares of
Class A Common Stock set forth below:

  No. of Shares                            Name and Address of Assignee
      -------------                            ----------------------------


and does hereby irrevocably constitute and appoint as attorney
___________________ to register such transfer on the books of ________________
maintained for the purpose, with full power of substitution in the premises.

  Dated:_______________, 200_.


                                         -------------------------------------
                   By:
                                             ---------------------------------
                     Name:
                                                   ---------------------------
                     Title:
                                                   ---------------------------


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<PAGE>

               SUBSCRIPTION FORM

        (To be executed only upon exercise of Warrant)

  The undersigned registered owner of this Warrant irrevocably exercises
this Warrant for and purchases __________ of the number of shares of Class A
Common Stock of Amerigon Incorporated, purchasable with this Warrant, and
herewith makes payment therefor, all at the price and on the terms and
conditions specified in this Warrant and requests that certificates for the
shares of Common Stock hereby purchased (and any securities or other property
issuable upon such exercise) be issued in the name of and delivered to
_____________________ whose address is ____________________, and if such shares
of Common Stock do not include all of the shares of Common Stock issuable as
provided in this Warrant, that a new Warrant of like tenor and date for the
balance of the shares of Common Stock issuable thereunder to be delivered to the
undersigned.

  The undersigned represents that such shares of Class A Common Stock
acquired pursuant to exercise of this Warrant will not be sold other than in
compliance with applicable securities laws.

  Dated:_______________, 200_.


                                         -------------------------------------
                   By:
                                             ---------------------------------
                     Name:
                                                   ---------------------------
                     Title:
                                                   ---------------------------

                   Address:
                                                  ----------------------------

                                             ---------------------------------


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