No lights other than headlights?

[Cntymnty77]

I got in the blazer the other day to move it and I went to turn the lights on and all I had were headlights, no tails or dash lights. I checked (I think) all the fuses and they looked good. Ive got a newer light switch in the dash but I’m not sure if it went bad already or not. Any ideas?

 

[Can Can]

Could be a bad ground on that circuit?

 

[6872xtc]

I would bet that you lost power to the marker lights somehow. The grounds should be split as far as each end of the truck. I would start by checking for power with a test light or multi-meter at the fuse and the plug terminals at the switch. But I would also be curious if there is a problem at the junction for the wiring at the firewall.
Did you get the dash lights fixed? I can't remember.

 

[Cntymnty77]

I would bet that you lost power to the marker lights somehow. The grounds should be split as far as each end of the truck. I would start by checking for power with a test light or multi-meter at the fuse and the plug terminals at the switch. But I would also be curious if there is a problem at the junction for the wiring at the firewall.
Did you get the dash lights fixed? I can't remember.

No, the only thing that has power is the headlights, no other lights. I thought I had finally caught all the electrical gremlins away..

 

[diesel4me]

First thing to check is to see if any power comes from the brown wire out of the fuse box that powers the tail & marker lights..
If none,then you'll have to hunt down where it lost power..

See if any smaller wires off the battery negative post that ground to the radiator support are all intact..

Look and see if its had a trailer hitch added,many wiring issues arise from hacked harnesses and improper wiring there,or corrosion..also check the harness plugs where it joins near the rear of the frame..

Sometimes fuse boxes corrode in between the two halves where the box & harness can be unbolted from the firewall and cause intermittent failures ..usually light switches don't fail very often unless you've overloaded them by adding multiple aftermarket lights and use the OEM switch..

 

[Cntymnty77]

Would it make a difference if the light for the license plate was unplugged? I wouldn’t think it would but I’m just trying to trouble shoot while I’m at work and don’t have the truck here. I stopped working after I got done with the lift. The only things I touched where the ground and other wire for the new tank and unplugged the license plate light when I removed the bumper.

 

[MEMO43]

Have you tested/checked the light switch or fuses to the lights.
I know it seems silly, but you have to remember sometimes its the little things that gets us

 

[dyeager535]

I got in the blazer the other day to move it and I went to turn the lights on and all I had were headlights, no tails or dash lights. I checked (I think) all the fuses and they looked good. Ive got a newer light switch in the dash but I’m not sure if it went bad already or not. Any ideas?

IIRC the dash light power comes directly off the headlight switch, thus why you can dim them with the knob. If those don't work, but headlights do, my first guess would be something wrong with the headlight switch itself.

You've tried pulling the switch out to the first notch, for parking lights?

 

[Cntymnty77]

Have you tested/checked the light switch or fuses to the lights.
I know it seems silly, but you have to remember sometimes its the little things that gets us

Yeah, I checked all the fuses and didn’t find anything blown.

IIRC the dash light power comes directly off the headlight switch, thus why you can dim them with the knob. If those don't work, but headlights do, my first guess would be something wrong with the headlight switch itself.

You've tried pulling the switch out to the first notch, for parking lights?

The switch is new but I suppose it could have gone out again..

 

[dyeager535]

Have you just tried wiggling the connector? The "escutcheon" (nut thingy that holds the switch to the dash) is tight? I want to say the switch uses that for a ground.

 

[6872xtc]

I know that you said that you looked at the fuses, but did you check them with a test light or multi-meter? Or was it pull out and look at them.
And I believe that the light switch needs to be grounded for the dash lights, not the marker or headlights. I bet that's what @dyeager535 was thinking. (?)

 

[dyeager535]

I know that you said that you looked at the fuses, but did you check them with a test light or multi-meter? Or was it pull out and look at them.
And I believe that the light switch needs to be grounded for the dash lights, not the marker or headlights. I bet that's what @dyeager535 was thinking. (?)

Yep, something in there. Had to check the electrical diagram, GM references a specific circuit number for ground, but it's not on the wiring connector, so it must be through the escutcheon, as I'm calling it.

I just remember a long time back I had some sort of light issue, and the loose switch was the issue. Well, that and an aftermarket dimmer portion that fell apart upon first use.

 

[Dan Myers]

These all are good things to check. I applaud all of these suggestions. In addition, check the dimmer switch and the turn signal switch. All lighting goes through the turn signal switch. My friends 72K5 recently lost all power except to the headlights. We changed that out and WALA.
About two years ago, I lost power to my lights on my 67 4x4 K10 and it turned out being a dimmer switch.

My bet, it will be something mentioned in these post.

 

[caseycraig]

I would bet that you lost power to the marker lights somehow. The grounds should be split as far as each end of the truck. I would start by checking for power with a test light or multi-meter at the fuse and the plug terminals at the switch. But I would also be curious if there is a problem at the junction for the wiring at the firewall.
Did you get the dash lights fixed? I can't remember.

Sorry to dig this one up - but I'm having a similar issue. Are you saying that power/grounds to the marker lights in the front could cause none of the lights in the rear to work?

 

[rampage]

Sorry to dig this one up - but I'm having a similar issue. Are you saying that power/grounds to the marker lights in the front could cause none of the lights in the rear to work?

Might be best to start a new thread where you specify exactly what your problem is, when it started and what you’ve checked so far. Also, as with any repair job, the correct tool is a must. In this case it would be a multimeter. If you don’t have one then get one and learn how to use it, we can help if needed.

 

[caseycraig]

Might be best to start a new thread where you specify exactly what your problem is, when it started and what you’ve checked so far. Also, as with any repair job, the correct tool is a must. In this case it would be a multimeter. If you don’t have one then get one and learn how to use it, we can help if needed.

Done. Thank you.

 

[6872xtc]

Sorry to dig this one up - but I'm having a similar issue. Are you saying that power/grounds to the marker lights in the front could cause none of the lights in the rear to work?

As far as I know, the front and rear marker lights are split up in the cab at switch, or the firewall junction. I can't remember which exactly, but they are definitely split up into 2 different sections of the firewall junction.