Dash Lights Don't Illuminate

[JAKE]

My son has a 96 LT1. His cluster works fine, but all other dash lights are out.

The dimmer works and controls the cluster, but CIC, headlight control, door lights, shifter, etc. are out.

We checked each any every FUSE and all are good.

Where should be go next.

Thanks for any help.

Jake

 

[ecss]

The Incandescent Power Driver supplies 12 volts or less depending on the dimmer switch to the bulbs/items you mentioned.

Remove the driverside black plastic footwell panel.

Lay on your back and look up around the middle/LH side of the steering column. Mounted on a plate and held on by one bolt is the Incandescent Power Driver.

If you can't see it, you might have to remove the carpeted panel and metal plate below the steering column that the diag. connector is mounted to.

It's a metal heatsink around 3x3 inches with a power transistor mounted on it. It has a 4 pin white Molex type connector going to it.

Pin A is not used
Pin B has 2 Dark Green wires
Pin C has a Brown/white wire
Pin D has a Brown wire.


To bypass the power driver, unplug the connector and use a paper clip and short Pin D (Brown wire) to Pin C (Brown/white wire).

Turn the headlight switch to Park or Head and the backlight bulbs should be at full brightness. If they are, the transistor is bad. I believe the dealer still sells the part. 90-96 C4's used the same part.

The Incandescent Power driver is shown in the top picture.

 

[JAKE]

Outstanding response! It's MUCH appreciated. When my son comes home from West Point for summer break next month, I'll show him your post and let him "have at it".

I could do it for him, but my thinking is it's best for him to get this hands-on experience.

Thanks much.

Jake

 

[JAKE]

Well, I decided to cut my son some slack, so I started working on the dash light problem this afternoon.

I removed the plastic side plate and after not being able to see very much, I dropped the carpeted panel and then the metal support pan.

At about this time I began running out of daylight and not being sure which bolt I should remove to access the IPD, I decided to leave it until tomorrow.

I saw one bolt/screw which looks like it has a 10mm or slightly smaller head. It's bright/shiny colored, not dark like many of the other panel bolts I'd removed.

Any tips and clues as to how to identify the "right" bolt or any other info would be appreciated.

Thanks,

Jake

 

[JAKE]

Okay, here's what I came up with after spending several hours upside down under the dash on my son's 96:

The IPD ISN'T mounted as shown in my 96 FSM. The FSM shows a single bolt coming up from the bottom which looks like it would easily accessible. Nope, not the case on my 96. The tiny mounting bolt enters from the side, high up and is not easily accessible.

In order to access it, I had to remove the plate that holds the steering column. Even then, it was a real PIA to access the bolt which holds the IPD to the dash.

So, using the info supplied by "ecss" (many thanks for that), I ran a jumper wire between the two brown wires and BINGO!, the dash lights now illuminate.

So based on that, I know that the IPD is dead in the water. Since I figure all it does is allow dimming capability, I've decided just to leave the jumper wire in place and do without the dimming function, that is unless "ecss" advises me that'll cause a problem down the road.

Jake

 

[Paul Higg]

Hey Jake, this was a VERY informative set of posts.

 

[ecss]

You can leave it jumpered just make sure nothing can short out.

The Delco part number is D1509b
You can order it online for around $36.00 plus shipping. http://www.partsamerica.com Input D1509b in the search box.

You can also order it online from this GM dealer.
GM Part#1995263. $32.00 plus shipping from
$235 LB7 injectors PartsZoneOnline - Your Source For Discount Genuine GM, ACDelco, and Mopar Parts They're located in PA.

Or you can fix it for a couple of dollars by replacing the blown transistor by using a 2N3055 transistor.

 

[JAKE]

You can leave it jumpered just make sure nothing can short out.

The Delco part number is D1509b
You can order it online for around $36.00 plus shipping. http://www.partsamerica.com Input D1509b in the search box.

You can also order it online from this GM dealer.
GM Part#1995263. $32.00 plus shipping from
http://www.partszoneonline.com They're located in PA.

Yep, that's it! Mine's mounted in a verticle (on edge) position with a screw through the round hole.

Thanks for the parts ordering links. I BOOKMARKED them into the "Favorites" section of my browser.

Jake