What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

All my lights flash.

doonjumper

doonjumper

1/2 ton status
Joined
Mar 9, 2001
Posts
948
Reaction score
4
Location
Visalia, California
Gm truck V3500, headlights dont work right (new switch), ALL turn signals flash at same time (both right and left), Brake lights flash, lights go out when brake switch is pressed, fuel pump relay opens and closes to the rhythm of the flasher, inside/cluster lights flash, no marker lights at all. Almost every circuit flashes

Heres what I have done so far....New headlight switch, tore apart the steering column and inspected wiring, went through entire loom and fixed ALL the issues (many wires just twisted and taped. Now they are crimped), Separated the fuse block and found hard, dried up, gunk that I assume was once electrical grease. Took ground leads off, wire wheeled surfaces and re-installed. Grounded to frame and back to body. No change :confused:


Any idears?
 
These sort of things can be fun. When you have multiple symptoms, probably related, it is usually best to pick one problem and concentrate on it.

Usually when you find that problem, you have found the solution to the rest.

What worries me, is your having to repair splices. Normally this sounds like a bad ground, but in this case, you may have crossed wires

Unless you have daytime running lights, the headlight system is fairly simple and not all that involved with the other systems.
It might be the best point of attack.

What is it doing wrong?

Also, you need to check ground wires instead of just connections. A main ground wire with corrosion or broken wire inside the insulation might look good but still be bad.
You might try grabbing a long heavy piece of good wire, clamping it directly to the ground terminal of the battery, and hooking it to various places while the problems are occurring to see if they stop.
 
Directional switch or 4 way flasher switch internally messed up maybe??...is the truck new enough to have a body control module??....I've seen them go south and cause weird issues...
 
Fordum said:
These sort of things can be fun.

What is it doing wrong?
Click to expand...

Fun if it's not yours LMAO!

As to what lights are doing.....Im outside and here is the play by play; (all bulbs are new and correct style)


1) Key and all switches in off position..brake lights are flashing.... 1157 bulbs in rear, no rear marker lights.
2) front turns are flashing.... 1156 bulbs in front
3) marker lights are flashing (front only)
4) cluster lights flashing
5)Turn on headlight switch (key on position) and headlights flash. no change to above mentioned.
6)fuel pump relay starts cycling off and on to flasher rhythm :haha:
7) click high beams and they flash with no change to above mentioned
8)turn on the marker lights with headlight switch with no change. Still no rear marker lights.
9)connect the brake light switch under dash and all flashing stops.
10)step on brake and all symptoms mentioned above come back

Couple of other issues;
1) fuel pump relay turns on with light switch,
2) took light switch out and tried to jump the red to the brown and (or any other color) no lights. I tested the backside of the headlight switch plug and and I have power at the red but not at the brown. Dosent matter what wire I test (when jumped from red) its the same, power going in but no power at whichever wire is jumped. Checked jumper wire and it is good.
 
diesel4me said:
Directional switch or 4 way flasher switch internally messed up maybe??...is the truck new enough to have a body control module??....I've seen them go south and cause weird issues...
Click to expand...

Ill check that out. Not sure if it has a BCM. I dont even know what that is or does to tell you the truth lol.
 
OK, I'm at work, and supposed to be doing other stuff, but here goes.
First, what year and model are we working with? I have several schematics on the computer, but don't know which one to check.
Next, how many wires on the brake switch? Seems weird that it stops when you plug it in and starts when you hit the brake.

Also, when its flashing, what, if anything is making a clicking noise? I assume the fuel pump relay is, but I'm not sure that what is happening is what you think is happening.
Flasher modules are not designed to flash that much load. When emergency vehicles flash their headlights, there is a relay doing the main work.

This sounds like a main power relay that is not getting full power. If you have ever tried to crank a truck with an almost dead battery, you will hear the starter solenoid chattering.
What is happening, is there is enough power to pull in the solenoid, but when the starter loads the dead battery down, the voltage drops too low for the solenoid to hold and it drops out.
As soon as it does, the battery has enough power to let it turn the solenoid back on again.

In this case, I am beginning to suspect that a main relay is not getting full power. It turns on, all the lights come on, and the voltage drops too low and it turns off again.
 
It is a 89 Chevy Crew Cab v3500 4x4.

4 wire on the brake switch. 2 underneath and 2 facing the driver.

The fuel pump relay is flashing (when plugged in. I can feel it flashing) and the flasher module that is in the fuse block. I can hear it and feel it.

Funny you mentioned the starter chattter. The battery went dead yesterday while I was trying to diagnose this issue. I tried to start truck and solenoid did chatter....:waytogo: good call. Ill check this issue out.
 
Hey Steve, you say that the front bulbs are 1156? Is that a typo? You mean 1157?
If that is true, it would cross the turn and park light circiuts.

That's all I have to contribute....
 
6872xtc said:
Hey Steve, you say that the front bulbs are 1156? Is that a typo? You mean 1157?
If that is true, it would cross the turn and park light circiuts.

That's all I have to contribute....
Click to expand...

The 1156 is single filament. 1157 is double filament or am I missing something?
 
Sounds like the PO messed the wiring up bad. You may be better off getting a different wire harness.
 
He is right. Your front sockets should have a brown and black wire in both, with black being ground and brown being parking/running lights.

Then the right should have a blue and the left a light blue for the turn signals.

An 1156 will fit in an 1157 socket, but will tie the two circuits together like he said.

You need to check and see what wires are actually there.
 
You must log in or register to reply here.

Latest Posts

Top Bottom