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), Chevy Technician
Category: Chevy
Satisfied Customers: 29455
Experience:  GM Grand Master Technician 2007. 14 years experience.
10949255
Type Your Chevy Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

Chevrolet 2500hd: I am changing lights daughters truck

Customer Question

I am changing lights for my daughters truck and noticed that I have no power at the DTRL bulb plug. Ive checked all of the fuses I can find and they all seem fine
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.
Hi there, I am Cam. Can I get your name please? When ou tried to check the bulbs, did you have the engine running, and shifter in drive? Those lights do not come on less the vehicle is in a gear. If you have not tried that, can you check that and see, then let me know?
Customer: replied 1 year ago.
Hi, I'm Dan. I'll check that
Expert:  GM Tech (Cam) replied 1 year ago.
Hi Dan. Perfect. Let me know.
Customer: replied 1 year ago.
I checked and the DTRL do not come on in gear. The voltage in gear is only 0.15
Customer: replied 1 year ago.
I also noted that the bulb receptacle is discolored as if it has been very hot
Expert:  GM Tech (Cam) replied 1 year ago.
Ok, if you remove the DRL relay and jumper the pins 30 to 87 using the numbers stamps on the bottom of the relay, do the lights come on?
Customer: replied 1 year ago.
I'll check
Expert:  GM Tech (Cam) replied 1 year ago.
Its possible the power terminal is also damaged. Check the wire going in. If you find nothing then lets check the area under the fuse block under the hood.
Customer: replied 1 year ago.
When I jumper between 30 and 86 they come on
Expert:  GM Tech (Cam) replied 1 year ago.
Are they opposite corners to each other?
Customer: replied 1 year ago.
Yes
Customer: replied 1 year ago.
Does that mean the relay is bad?
Expert:  GM Tech (Cam) replied 1 year ago.
Did you try swapping the relay for another one with the same numbers from the fuse block like the AC relay or something ?
Customer: replied 1 year ago.
I'll try that now
Expert:  GM Tech (Cam) replied 1 year ago.
Possibly a relay .
Customer: replied 1 year ago.
I couldn't be that lucky. It still doesn't work
Expert:  GM Tech (Cam) replied 1 year ago.
Ok, You had it running and in drive outside where it is bright?
Customer: replied 1 year ago.
yes. and the headlight switch in auto
Expert:  GM Tech (Cam) replied 1 year ago.
Ok, do 2 pins for the DRL relay have power all the time?
Customer: replied 1 year ago.
Ill check
Customer: replied 1 year ago.
Yes 30 and 86
Expert:  GM Tech (Cam) replied 1 year ago.
OK, so the 4th pin is the BCM ground control. So take the fender brace out, lift the whole big black cover off and flip up the fuse block. Inspect under there for any wiring issues, rodents, corrosion and such. This cannot be done from the top, it must be removed and I mentioned.
Customer: replied 1 year ago.
OK
Customer: replied 1 year ago.
I don't see any damage or corrosion. just some dust
Customer: replied 1 year ago.
are 30 and 86 not supposed to have power?
Expert:  GM Tech (Cam) replied 1 year ago.
They are. 2 pins get power, then one of those, 86 supplies power to operate the relay, the Body Control Module (BCM) controls the ground through pin 85 which connects pins 30 to 87 which goes to the light.
Customer: replied 1 year ago.
everything looks good under the fuse block
Expert:  GM Tech (Cam) replied 1 year ago.
Ok so do you have the means to scan the body control module?
Customer: replied 1 year ago.
No
Expert:  GM Tech (Cam) replied 1 year ago.
Ok so this will add an element of difficulty to this. Those lights are controlled by the BCM using the shifter position and dash light sensor. SO far we know the lights work, meaning in the dark the auto lights come on and that your DRL's don't. So we need to check that wire from the BCM to the relay. Are you able to get at the back of the BCM which is under the steering column?