HVAC and Speedo Lights not working [Archive] - GrandAmGT.com Forum


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04-07-2004, 04:59 PM
I tried to install a set of vent lights and blew the fuse marked inst. lights and the speedo lights quit working replaced the fuse and they still don't work. I thought I needed a new dimmer control switch. I ordered one from the dealer, installed a few minutes ago and the lights are still not working. The fuse is not blown, I have checked it many times. I took the vent lights out for the time being.

Anyone have any idea what the problem might be?

04-07-2004, 06:48 PM
There is also a lamp dimmer module in vehicle which is the real power source for dimmer circuit (not the switch). Maybe these lights you added exceeded what it can handle. I think those things are rated for 4 Amps (and I don't know what the base vehicle draws). This module is located "On the left side of the instrument panel, near the brake pedal". It has 3 wires going to it. it is mounted on a heat sink and usually attached to a metal bracket.

YEL wire is power feed from INST LPS fuse
DK-GN wire is control signal from dimmer switch
GRY wire is the output to bulbs

04-07-2004, 06:54 PM
Would you happpen to know the part # for that.
Ive checked almost every fuse in the car trying to figure this out.
I'm going crazy. :banghead

04-07-2004, 07:03 PM
Give me a few minutes and i will find it for you. At least the GM part number.

If you are working on it right now try this out just as a test........... when your Park Lamps are on jumper the YEL and GRY wires together (DON'T LET THE JUMPER TOUCH METAL OR YOU WILL BLOW A FUSE AGAIN).

Does your backlighting now turn on? It will be at full intensity

04-07-2004, 07:08 PM
Not working on it right now,
I have to leave to go to work.
But I will be working on it tomorrow afternoon.

04-07-2004, 07:13 PM
OK it took me a little longer than expected.

GM P/N 1995263. Official name is Dimmer Asm - I/P LP

I also confirmed it is rated for 4 Amps

I checked Parts Catalog and looks like service uses the same part number (BTW the ACDelco P/N is #D1509B).

Good Luck!!

04-08-2004, 07:10 AM
thanks man. only $20 from gmpartsdirect.com
Going to try to jumper the wires the evening.
If the lights come on with the jumper that means I need the lamp dimmer module right?

04-08-2004, 03:35 PM
Well, there is still a slight possibility that it could be something to do with the control circuit to the dimmer module from the dimmer switch but you said you already tried a new switch and the fact that this all started happening after adding additional loads to the dimmer circuit all point to that module having been damaged.

Jumpering around the module just insures that the rest of the wiring is OK.

04-08-2004, 05:38 PM
where exactly is the lamp dimmer module located? I looked under the dash and didn't see anything like what you described.

04-08-2004, 08:36 PM
where exactly is the lamp dimmer module located?http://www.geocities.com/raj380/malibu_nolf/images/lampdimmer.jpg
Give this a shot. See part with the "1" that is it.

The arrow is pointing forward in vehicle. So this module is somewhere in the vicinity of the steering column.

You are making me call upon all of my resources lol

Hope you consider the "G6" when it comes out - I know a heck of a lot more about that vehicle :)

08-18-2010, 11:40 AM
Do you have any pictures?