dashboard light fuse ?

[jim659]

Does anybody know where the fuse or maybe the bulb for a 2004 dashboard is? I have no dash lights or any lights when you switch from 2wheel to 4high or 4low. I can't find it in the manual.

Thanks, Jim

[northofthe52nd]

I recently had my injectors replaced and while I was in the shop, I had them check out the 4wd panel light. Turns out several other units in the new car lot had the same problem. They replaced the panel. $100 warranty deductible on both the truck and $100 on the engine.

2002 crew cab 2500 short bed Duramax/Allison

[More Power]

I've learned that many of the truck's electrical systems are controlled by applying a ground circuit when activated. The interior courtesy lights are controlled by applying a ground to the CTSY circuit when a door is opened (for example).

As another example, one of the pins of the front axle switch is connected to ground when the axle is engaged. For another, there are four Hall-Effect switches in the transfer case that connect to ground when a range is selected (2H, 4H, N or 4Lo). When in either 4H or 4Lo, the four wheel engaged light on the instrument panel is supposed to illuminate, again by grounding a circuit.

So, it might be possible that when a system ground is connected, it shorts or interferes with something in the instrument panel. The instrument panel is not a serviceable item - other than replacement.

MP

[jim659]

Everything in the dash works except the lights for driving at night. There's no fuse or bulb for this?

[More Power]

I'll do a little research tonight and post a series of tests for you tomorrow.

In the meantime, do all dimming interior lights on the dash (aside from the instrument cluster) go out? There are dimming lights used in the light switch, the 4WD panel, the radio, and heater/AC controls etc.


MP

[Turbo Al]

To correct my dash light problems they replaced a "MODULE" it didn't help and I am 100% sure it is the nsbu switch on the trans causing the problems. If you want I will dig up the paper work on the dash light module and post the Part #.
Al

[mdrag]

Some time ago, I thought I had dash light problems on my 2001. The fuses checked okay, and as I was pulling the trim from around the instrument cluster to investigate further, I realized that the dimmer switch was turned all the way down...DUH :eek: ...and I didn't remember messing with it.

[jim659]

Everything dims like it should , door panels ,odometer and everything else Ijust have no dash lights or 4wheel selection lights. I can't even find a fuse or sub fuse labeled for the dash lights .

Thanks for everybodys help, Jim

[More Power]

There is an "ILLUM" fuse located on the fuse panel, on the left side of the dash, which provides an interior dimming circuit for all dash components.

Some of the interior switch panels including the instrument cluster utilize LED's and or a combination of LED's and bulbs. Those that use LED's get an LED dimming signal from the Body Control Module, which is used to activate a logic control in the dimming circuit for each respective switch panel or instrument cluster.

The Instrument panel, Transfer case shift control switch, inflatable restraint module disable switch (used on standard & extended cab trucks) and the radio all get an LED dimming signal from the BCM.

The HVAC control switch panel does not use LED's, and the interior lamp dimming circuit will be unaffected by the BCM.

So, if the HVAC panel lights up with the lights on, and dims normally, the "ILLUM" fuse is OK.

To test further, remove the instrument cluser and check pin A7 (gray wire) for a dimming power source. If it is there, the instrument panel is likely OK.

Since the transfer case control switch "and" the instrument panel dimming lamps aren't working, the problem is more likely to be a BCM or a related wiring problem. Check continuity of BCM C2-A 12 (PPL/Wht wire) to Instrument cluster connector B5 (gray wire). If continuity is good, I'd suspect the BCM.

MP

[Minn-kota]

I'm fairly certain there isn't an "ILLUM" fuse in the 2003+ trucks.... I know I tried to look for one when installing my pyro/boost gauges and no luck.

[jim659]

I could'nt find it either, that's whats got me so baffled. Tommorow I'm going to try More Powers ideas and see what happens. It seems like something that would definatly be fused.

[Minn-kota]

Looking into it further, I found a fuse called "SEO IGN" in the underhood electrical center. It's description is "DEFOG relay, Instrument Panel Cluster (IPC)". 10 Amp fuse.

Also one called "IPC/DIC". You said your DIC is functioning, but doesn't hurt to check that fuse as well.

Another "SEO B1".....IPC, rear fog lamp relay, overhead console, roof beacon switch.