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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29518
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2005 Chevrolet Tahoe: auxiliary..the under-the-hood fuse box is good

Customer Question

Where are the fuses associated with the front auxiliary power outlet in a 2005 Chevrolet Tahoe? The fuse in the under-the-hood fuse box is good. Is there an in-line fuse for this outlet as well?
Submitted: 6 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 6 years ago.

Hi, I'm Cam
I will answer your question quickly but we may need to discuss this further. Please reply to continue the discussion.

There is another fuse the CIGAR fuse. THat is in the underhood fuse block as well. Check that fuse and see.


Expert:  GM Tech (Cam) replied 6 years ago.

The cigar fuse is circled in red.


Customer: replied 6 years ago.

I've checked and replaced the fuses labeled "AUX PWR" (20 amp) and "CIG LTR" (15 amp) fuses in the UNDERHOOD Fuse Block. My cigarette lighter is working fine. I've also checked the fuse labeled "AUX PWR 2" in the Instrument Panel fuse block.


I wanted to know if there was a hidden or additional "In-line" fuse that supports the "Auxiliary Power Outlet" that is mounted just to the left of the Cigarette Lighter outlet.


If there is an in-line fuse that needs to be checked or if I need to get to the back of the Auxiliary Power Outlet to repair or replace it, what panels need to be removed and the process associated with that.


Expert:  GM Tech (Cam) replied 6 years ago.

No sir, no hidden or inline fuses at all, just the ones that you found on that fuse block, CIGAR, AUX 1 and 2. DO those have power with a test light?


Customer: replied 6 years ago.
I just checked both with my voltmeter. The "CIG LTR" has 12.2 VDC across it. The "AUX PWR" has no voltage (actually 0.033 VDC" across it.
Expert:  GM Tech (Cam) replied 6 years ago.

Are you testing across the 2 parts of the fuse?


Customer: replied 6 years ago.
I have removed each fuse one at a time and I'm sticking my probes into the two sockets of the individual fuse block to get the voltage reading for each fuse location. It appears that the "AUX PWR" fuse is not getting the 12 VDC power from the battery side of this circuit. I've tried looking in Haynes and Chilton books for the circuit diagram but none show this portion of the circuit.
Expert:  GM Tech (Cam) replied 6 years ago.

Ok, lets try it this way. put one lead of the meter to ground and then test each fuse leg.


Customer: replied 6 years ago.
With the fuse removed I touch the negative (black/common) probe to the negative side of the battery and I touch the positive (red) probe to the left fuse leg location I get -12.7VDC. When I keep the negative probe on the negative side of the battery and touch the red probe to the right side fuse leg location I get 0.03VDC.
Expert:  GM Tech (Cam) replied 6 years ago.

Ok, that is expected and proper. Only one leg will have power and testing over the 2 legs like that will not give good results if there is anything plugged into the outlets. Can you repeat that test for the CIGAR, and both AUX fuses?


Customer: replied 6 years ago.

Okay, I measure the voltage on each leg of the other two items. I connected the negative probe again to the negative side of the battery and touched each leg of "CIG LTR" fuse location. One side had a voltage of 0.03 VDC and the other had a voltage of 12.7 VDC.

The measure values of the "AUX PWR 2" fuse location were also 12.7 VDC on one side and 0.03VDC on the other.

Anticipating your next move, I reinstalled all of the fuses in their proper location. I then measure the voltage from the negative side of the battery to the outer metallic portion of the Cigarette Lighter Outlet. The voltage there was 0.03VDC. I then measured the voltage from the negative side of the battery to the center back part of the cigarette lighter outlet. It read 12.7 VDC.

I measured the voltage from the negative side of the battery to the Rear Auxiliary Outlet (AUX PWR 2) circuit in the cargo area of the vehicle. Its readings were similar to the Cigarette lighter readings... 0.03VDC on the outer metallic shell and +12.7VDC on the rear metallic portion.

Finally I measured these values for the faulty Auxiliary Power Outlet next to the Cigarette Lighter. It read 0.03VDC for both the outer metallic shell and the rear center metallic portion verifying that it was not getting power from the battery on one side of this circuit.

What do I do next?

Expert:  GM Tech (Cam) replied 6 years ago.

Ok, which location exactly is the faulty plug at?

PS, GREAT DIAGNOSIS!! I wish all my customers went this extra mile.


Customer: replied 6 years ago.
It is the AUX PWR circuit or what is called the Auxiliary Power Outlet (the one that is mounted right next to the Cigarette Lighter). I've looked under and around this panel and even tried to remove two of the screws that secure it but was unable to see the rear of this outlet or any cable connections to it.
Expert:  GM Tech (Cam) replied 6 years ago.
Ok take a nail or 2, about 3/4" in on 2 spots opposite are small black tabs flush with the case. Push a nail in each to release the oultet and pull.
Customer: replied 6 years ago.
I've been trying your method but I haven't been able to push them in far enough to disengage. In fact they don't seem to move at all or disengage. I even tried a modifed inner spanner pliers to push both tabs that are located about 3/4" in from the outside surface of the outlet. They are about an 1/8" x 3/16" boxes with black tabs in them. I tried to attach a picture but it blocked this text so I thought I'd better respond. Any additional suggestions?
Expert:  GM Tech (Cam) replied 6 years ago.

That seems too wide, but there are 2 and about 1/8 square.

Either way, that pushes out and the housing or plastic stays, and the metal pulls. Try again but slip a small flat blade screw driver behind the lip to start pulling the insert or metal out.


Customer: replied 6 years ago.
Well, I finally got it out. It wasn't easy. I disconnected the battery before I began. I did as you suggested and finally got a small enough screwdriver under the edge of the metal portion. I then wrapped some tape around some channel-locks (to not damage the metal portion and tweeked it back and forth until I got it out. I disengaged the connector on the back of the outlet and measured the voltage across the two terminals on the connector. When I cranked the truck I got a voltage of 14.4VDC. I then tested the conductivity of the metallic outlet between the tabs on the rear of the outlet and the interface surfaces on the front. I was able to get conductivity between the copper tab and the outer metallic shell but I was unable to get any reading between the silver tab and the center metal part on the front-side of the outlet. I'm assuming I've got a bad outlet casing. I did test conductivity between the rear center metal part and the front middle part but it was sporatic. What do you think? Is this the problem?
Expert:  GM Tech (Cam) replied 6 years ago.

Yes I suspect the outlet. I see that often. They are cheap from GM, 10 or so at the most. Then they just push in.

The tool from GM for removing it makes it easy, it is a T that is the perfect size.


GM Tech (Cam) and 5 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Thanks for all of your diligent help.
Expert:  GM Tech (Cam) replied 6 years ago.

That is what I do best.

Thanks for using Just Answer. If you want me to answer your next GM or GM product question, please put "For GMTECH Cam to Answer" and I should get it. Thanks and have a great day!!