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TBC 2A Fuse Keeps Blowing 15 amp PLEASE help me!

11902 Views 6 Replies 5 Participants Last post by  Playdrv4me
2004 Escalade 6.0 awd - new optimus battery (red top) and had altenator and battery checked - everything is normal on their tests.

The TBC 2A fuse controls the dashboard lights it calls for a 15 amp fuse which keeps blowing. If I put a 20 amp fuse in it will work good for a few minutes and then the dash board (heater lights, dash lights, rear control lights etc..) all start to blink.

Actually the speedometer will glow brighter when the other lights dim out and then the other lights will come back to normal and so will the speedometer lights. So it fluctuates power where the speedometer flashes brighter when the other lights dim and when the other dash lights come back to normal the speedometer dims down to normal levels. This blinking is at a rate of about 3 seconds, so - flash bright speedometer and dim out other dash lights for 3 seconds then - dash lights come back to normal light and speedometer dims to normal level for 2 seconds etc....

With a 20 amp fuse in there I can dim the dash lights but it is erratic where it isnt a steady dim it is sketchy at best while adjusting the dimming wheel.

If I put a 15 amp (what it calls for) in the TBC 2A slot, the second I turn over the key it pops it. I do not even know where to start diagnosing the problem.

If it were a ground issue wouldnt it blow the 20 amp fuse too?

What kind of "short circuit" could this be? Does anyone one know where I would look to see what exactly is controlled by the TBC 2A 15 amp fuse?
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Sounds like something you might have to take it to the dealer for.
Modern cars have electronic dimming modules rather than a rheostat like your 1939 Dodge. Instrument dimming problems can be VERY complicated.
I would take it to the dealer. If youve got an 04 your probably still under warranty, theres a serious short or internal fault in the IP.


Subject: IPC Lighting Inoperative TBC 2A Fuse Open - keywords cluster dim instrument light panel #PIT4365 - (04/24/2007)

Models: 2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT

2003-2006 Chevrolet Avalanche, Suburban, Tahoe

2003-2006 GMC, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

2003-2007 Chevrolet SIlverado Classic

2003-2007 GMC Serria Classic


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customer may bring in their vehicle stating that the Instrument Panel Dimming is inoperative. After initial inspection, you may notice the TBC 2A fuse that is located in the left IP fuseblock is blown.

If you experience this concern and can not isolate the source of the concern, inspect the wiring coming out of the IP relay block for a short to ground. Reports from the field have found issues with harness pictured below and the concern can usually be located 8 inches below the IP relay block.

(See Photo Below) The arrow shows where the harness rubs on the IP relay block support bracket near the holding clip. Remove the harness from the clip and inspect carefully. Repair as needed and insulate the edge to prevent a repeat occurrence.


Just performed a bulletin search. You can fix the problem yourself at home.

Left instrument panel fuse block. CAREFULLY trace the wiring harness from the bottom of the fuse block to a clip. In those 8 inches of harness, GM states they are finding short-to-grounds, which obviously will pop fuses.

So, you have a wire rubbing a clip, causing a short. Check that harness and fix it.
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Don't install bigger fuses to "test" circuits, all you end up doing is melting stuff.

It should be properly diagnosed. If you can't figure it out try to find a reputable shop with a good electrical person.
Playdrv4me said:
...theres a serious short or internal fault
As I mentioned before, thats what usually causes fuses to blow repeatedly like that.
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