Headlight control module question
Thread Starter
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
Headlight control module question
Can someone tell me if the headlight control module from a Firebird, Fiero, C4 and early C5 are all the same? I've read many different things and I would like to try to get a clear answer.
Has anyone used a headlight control module from a different GM car in a Corvette?
thanks,
Has anyone used a headlight control module from a different GM car in a Corvette?
thanks,
Thread Starter
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
I found this while cruising Google for "Fiero Headlight Control Module":
"There are only two wires connected on each motor. Green(/black) and grey(black), and they connect to the output (4-pin connector) on the headlight control module. The other connector (5-pin) on the module is the inputs. The two red wires are the continuous power from the battery through two fusible links, as in the 84-86 system. The white and yellow wires from the headlight switch are also the same, as is the ground."
Great description of the function of the headlight control module. While the above writeup is for a '87 and '88 Fiero, everything down to the color of the wires matches what is shown in the '91 FSM for the Corvette.
As ZR1Fred mentioned it look like the Fiero module will work in a Corvette.
"There are only two wires connected on each motor. Green(/black) and grey(black), and they connect to the output (4-pin connector) on the headlight control module. The other connector (5-pin) on the module is the inputs. The two red wires are the continuous power from the battery through two fusible links, as in the 84-86 system. The white and yellow wires from the headlight switch are also the same, as is the ground."
Great description of the function of the headlight control module. While the above writeup is for a '87 and '88 Fiero, everything down to the color of the wires matches what is shown in the '91 FSM for the Corvette.
As ZR1Fred mentioned it look like the Fiero module will work in a Corvette.
Thread Starter
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
Another great article about how the headlight control module works. Again it's for the Fiero but scroll down to the '87/'88 part of the page and it contains troubleshooting and a good writeup about how the system works. Note that all the wires in the Fiero are the same color as the Corvette.
http://www.fieros.de/en/articles/headlight.html
http://www.fieros.de/en/articles/headlight.html
Thread Starter
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
OK maybe this will help someone in the future:
Headlight control modules that will work with the Corvette:
'87/'88 Fiero (usually sell on E-bay for $5 to $15)
Firebird with module mounted on drivers side of the firewall just below the windshield (I picked mine up at the local bone yard for $10 working great in my '90 harness).
The above modules will work in '87 to '96 Corvettes and you will avoid the corvette tax by buying one from another model. These units are very robust so don't hesitate to buy a used one they normally last a long long time. Units sold USED and listed for the "corvette" are usually $60 and up.
There is also a plethora of other pontiacs, chevys, etc that has pop up lights in the later 80's/early 90's that may very well use the same module. I just can't say with 100% accuracy but my research indicates that the following cars use the same module:
Buick: Reatta (1988-1989)
Sunbird (1988-89)
these would be worth a try also.
hope this helps someone,
Headlight control modules that will work with the Corvette:
'87/'88 Fiero (usually sell on E-bay for $5 to $15)
Firebird with module mounted on drivers side of the firewall just below the windshield (I picked mine up at the local bone yard for $10 working great in my '90 harness).
The above modules will work in '87 to '96 Corvettes and you will avoid the corvette tax by buying one from another model. These units are very robust so don't hesitate to buy a used one they normally last a long long time. Units sold USED and listed for the "corvette" are usually $60 and up.
There is also a plethora of other pontiacs, chevys, etc that has pop up lights in the later 80's/early 90's that may very well use the same module. I just can't say with 100% accuracy but my research indicates that the following cars use the same module:
Buick: Reatta (1988-1989)
Sunbird (1988-89)
these would be worth a try also.
hope this helps someone,
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Not too sure if all of that is completely correct. My 87 has three separate headlamp motor control modules or actually 'relays'. There is a relay for each of the motors and an "isolation" relay. The purpose of the isolation relay is to change the ground at the motors to allow them to go up or down. The polarity of the motors changes based on whether or not the motor runs forward or backward.
Each of these relays were about an inch square and had their own harness and connector based on what it controlled All of the relays are mounted side-by side on a metal panel that was attached to the left front wheelwell panel
My 92 had a single electronic relay that controlled the headlamp motor operation. This relay had a pair of flat connectors that went to the headlight motors. The entire component was about 4 inches square and about an inch thick.
Each of these relays were about an inch square and had their own harness and connector based on what it controlled All of the relays are mounted side-by side on a metal panel that was attached to the left front wheelwell panel
My 92 had a single electronic relay that controlled the headlamp motor operation. This relay had a pair of flat connectors that went to the headlight motors. The entire component was about 4 inches square and about an inch thick.
Thread Starter
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
Not too sure if all of that is completely correct. My 87 has three separate headlamp motor control modules or actually 'relays'. There is a relay for each of the motors and an "isolation" relay. The purpose of the isolation relay is to change the ground at the motors to allow them to go up or down. The polarity of the motors changes based on whether or not the motor runs forward or backward.
Each of these relays were about an inch square and had their own harness and connector based on what it controlled All of the relays are mounted side-by side on a metal panel that was attached to the left front wheelwell panel
My 92 had a single electronic relay that controlled the headlamp motor operation. This relay had a pair of flat connectors that went to the headlight motors. The entire component was about 4 inches square and about an inch thick.
Each of these relays were about an inch square and had their own harness and connector based on what it controlled All of the relays are mounted side-by side on a metal panel that was attached to the left front wheelwell panel
My 92 had a single electronic relay that controlled the headlamp motor operation. This relay had a pair of flat connectors that went to the headlight motors. The entire component was about 4 inches square and about an inch thick.
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