How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29430
Experience:  GM Grand Master Technician 2007. 14 years experience.
10949255
Type Your GM Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

2004 Hummer H2. My rear left side market is out...saw it

Customer Question

2004 Hummer H2. My rear left side market is out...saw it working the other night but mostly it does not. Upon removal of mounting screws, the unit appears to be one integrated unit and the connector is too deep inside the body panel to reach. Thoughts?
Submitted: 1 year ago.
Category: GM
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam. Can I get your first name please? To help me get a better sense of your issue, can you tell me if your front marker lights work properly and if the license lights work properly?

Customer: replied 1 year ago.
Front left side marker works. My name is Al.
Expert:  GM Tech (Cam) replied 1 year ago.

Hi Al, how about the Tag lights in the back?

Customer: replied 1 year ago.
When I just got out of The car left side marker was working close the door turned on the lights all markers around the vehicle work except that left side marker. license plate lamps work. So what I see is that the lamp works intermittently it's not a bulb problem because it does work on occasion.
Expert:  GM Tech (Cam) replied 1 year ago.

There may be a bad connection at the junction block On the underside of the rear body near the center of the rear bumper. It is possible for the bulb to work intermittently. If the filament is broken, it can swing back into place and work the odd time, usually tapping on the bulb either makes it worse or makes it work. Its not often but it does happen. It could also be a socket issue. My suggestion is to remove the bulb, check it out and see if there is corrosion in the socket, even look to change the bulb.

Customer: replied 1 year ago.
The unit appears integrated, housing wiring, etc...not like others with obviously removable bulbs
Expert:  GM Tech (Cam) replied 1 year ago.

Very odd. Is this the side corner marker or is this the one that has the signal brake lights in it?

Customer: replied 1 year ago.
Thats my question... I have a replacement unit on the way but I can see no way to get to the connector to swap it out. I thought of replacing it as first course of action but can't do it unless I cut and splice
Expert:  GM Tech (Cam) replied 1 year ago.

The removal does require the panel to be removed so I would cut and splice myself.

Customer: replied 1 year ago.
I think it's something else as it works when I exit the vehicle and lock the car. Must be some relay. Replacing it when it works at consistent times will not fix the fact it does not work when I'm in headlights on mode
Customer: replied 1 year ago.
Anything further for you to suggest on this Cam? I will have to say I don't yet feel like I got any advice beyond my own common sense. Is there a relay I can take out reseat and replace? Do you know what relay that lamp uses?
Expert:  GM Tech (Cam) replied 1 year ago.

I have to run out. I am a FireMedic on shift today and I have a call. I Will open this up to other experts who can help you sooner.

Customer: replied 1 year ago.
Thank you Cam
Expert:  GM Tech (Cam) replied 1 year ago.

So I see no one has helped you yet. I have time now if that's ok. Posted are steps to replace that light properly.

Remove the rear door sill trim plate. Picture attached. Once it's off you can remove the harness from the body and replace the light.

  1. Firmly grasp and gently pull the rear door sill plate to disengage the retaining clips.
  2. Remove the rear door sill plate from the vehicle.
  3. Inspect for broken or missing retaining clips and replace as necessary.
Customer: replied 1 year ago.
I don't think it's the light itself cam. There's another issue that were not addressing. The light does work at odd times. For example it does work at night when the light switch is in the full on position however it will not work in the auto position this leads me to believe it's some sort of relay that is not functioning properly. Your thoughts ?
Expert:  GM Tech (Cam) replied 1 year ago.

OK but its ONLY that light or did I miss some other light that is not working?

Customer: replied 1 year ago.
Only that light. I don't see replacing it as it does work but not when it is supposed to
Expert:  GM Tech (Cam) replied 1 year ago.

Let me look into the schematic. One moment.

Expert:  GM Tech (Cam) replied 1 year ago.

So there is no direct connection to the back light with is odd. Does anything with the signal lights make it change?

Customer: replied 1 year ago.
No sir just tested
Expert:  GM Tech (Cam) replied 1 year ago.

So that is very strange. Its fed by the same power as the park lights and grounds with the signal lights. So unless there is a strange connection issue, I would say it’s a bad light. Can you test the wiring with a test light and confirm?

Customer: replied 1 year ago.
if other lights are on when theyre supposed to be on theres no reason why that one shouldnt be on unless the light itself is bad. No crazy relays to check? The odd thing is that it does work at times. Because this does not look like a fillament type bulb, i question that. Theres no way to replace this light unless i just remove the entire red bezel, clip the wires and splice in a new one. Thus tells me GM didnt plan on having to replace this light. As I have a replacement on the way (it cost about $120) I will install it based on your recommendation but logic says this isnt the answer. It doesnt flicker, it just isnt on when its supposed to be on most of the time, other times I see it working.
Expert:  GM Tech (Cam) replied 1 year ago.

It is not a regular bulb. It's an LED so it's not supposed to need replacing. No special relays or anything. I would check the wiring inside the body to be sure that's no shorting out or chaffing. You have the directions to get inside the panel to disconnect the light.

Customer: replied 1 year ago.
No Cam, I don't have the directions to get inside the panel. The one Gif file you posted does not tell me any steps. Perhaps you could email me the directions to***@******.*** that would be great I have the replacement LED
Expert:  GM Tech (Cam) replied 1 year ago.

I am on mobile but it's very simple, the sill plate on that side needs to be popped up then out and the connection is behind that.

Customer: replied 1 year ago.
Since the connection was so hard to get at, even with the ashtray popped out, I spliced in the brand new LED assembly. No luck, it does not work. I will watch it and see if it comes on and circumstances surrounding it.
Expert:  GM Tech (Cam) replied 1 year ago.

OK, if it does not work, reverse the wiring. LEDs do have a specific polarity.

Customer: replied 1 year ago.
I tried that.
Expert:  GM Tech (Cam) replied 1 year ago.

ok

Related GM Questions