Comments on: Dimmer Module

By: Cliff Harris

Cliff Harris — Tue, 22 Nov 2011 06:52:48 +0000

The 1N4001 is a 50 volt, 1 amp diode.
The 1N4007 is a 1000 volt, 1 amp diode.

There is no difference in the current rating for the 1N4001 series of diodes.

By: Rob Healey

Rob Healey — Sun, 13 Mar 2011 00:25:26 +0000

Hi Geoff, that is very valuable info,thanks, My guess is that the year would be late 80′s, does that sound right ?

Do you know any other Holden parts that fit C4′s?

By: Geoff

Geoff — Sat, 12 Mar 2011 20:48:30 +0000

I have found the same module is used in some commodores (not sure of year)it is located above steering column behind speedo it is usually just sitting there waiting to be unplugged

By: Cory

Cory — Fri, 13 Aug 2010 02:09:57 +0000

This page helped my fix my module in my 1984 Corvette , the problem was that there were no courtesy lights when opening the door , the light switch knob turned counterclockwise turned them all on , the hatch worked when the light switch was turned but not when it wasnt.
Problem was solved by replacing the GE transistor with a MJE 3055T , I also changed D1 IN4001 with IN4007 , this increases the allowed amperage to 7. This increased amperage will help with the burst amperage drawn when popping the hatch via the door switch.
All works now !!! Thank you for the transistor cross reference!

By: admin

admin — Wed, 23 Jun 2010 00:47:56 +0000

@craig, sorry, he was a personal friend who is an electronics wizz -he provided the circuit diagram and worked out what nearly all of the parts are.

That info should help anyone with a little electronics knowledge fix the module.

More than likely it’s the large transistor, in the TO 220 case, they get hot when the doors are left open.

Mine now has a HUGE transistor there with large heatsink and I’ve had no further problems. I still am careful not leave the doors open when cleaning or fixing something without disconnecting the battery though. BTW I have seen mechanics leave the door open for an hour!!!

By: craig

craig — Wed, 23 Jun 2010 00:09:46 +0000

hi, could you provide the phone num for the fellow who repaired yours thanks craig

By: Rob

Rob — Sun, 14 Mar 2010 06:00:40 +0000

Hey Rob it’s Rob, This article was very helpful to me also. I was able to get my dimmer module replacement from a Corvette Parts web site in the USA. The site is looking good. I hope you get a chance to play your keys once and a while.

By: admin

admin — Thu, 28 Jan 2010 22:37:02 +0000

@Blake – more than likely the Transistor in a TO 220 case is faulty – as pictured – they get very hot. Try replacing that.

All the info I have is here.

The other alternative might be to buy a dimmer kit from an electronics store like radio shack – must be 12 volt and able to handle say 4 amps to be safe.

By: Blake

Blake — Thu, 28 Jan 2010 08:13:27 +0000

Hey i loved the article.
I have a 1985 vette and the chevy dealer told me i need a new module but they dont make them anymore so i need another but i cant find one. so what do i do?

By: teleskopy astronomiczne

teleskopy astronomiczne — Tue, 29 Dec 2009 15:10:30 +0000

Very nice blog, your article is interesting, i have bookmarked it for future referrence