LED flasher

[heathbirkendahl]

I installed LED tail and front bumper lights. So i had to change the flasher wired it up and all works ok. Minus my head lights. It takes a few seconds for them to come one. Anyone else have this issue?

Thanks!
Heath

[VetteVet]

Most likely you have a bad connection or a bad ground in the circuit. The head light switch is powered by a red wire from the interior cab junction.
When you pull the switch knob out the power is sent to the dimmer switch by a blue wire and from there to the headlights by a light green and tan wire.

The tan wire is for the low beams and the light green is for the high beams.

The poor connection can be at any one of those three points.

Get yourself a multimeter and check the power on the blue wire in the dimmer switch harness as you pull on the headlight switch. Place the read lead on the blue wire and the black lead on a good ground and with the meter set on DC volts turn on the light switch and look for 12 volts. The meter should read instantly. If it does then the headlight switch is OK.

Plug the dimmer switch connector back on the switch and go to the left front headlight plug and pull the connector off and connect the meter with the red lead to the green or tan wire in the plug and the black lead to a good ground.

Again with the meter on DC volts, turn on the lights and you should see 12 volts almost instantly. If you don't then the dimmer switch is probably bad. If you do the headlight plug or the ground for the lights is probably bad.

The dimmer switches on these old trucks are very often the cause of problem with the headlights, so I would suspect that is your problem.
As and alternative to the meter you can pull the harness off the dimmer switch and jumper between the blue wire and the green or tan wire and try the switch. The lights should come on right away and if they do then the switch is the problem or the connector to the switch may be corroded.

This is the red power wire for the cab. It goes to the horn relay, the ignition switch, the fuse panel and the headlight switch, shown in the next picture.



The headlight switch in the lower right, notice the blue wire. It goes to the dimmer switch.



Here's the engine compartment showing the headlight wiring on the left edge.

[heathbirkendahl]

VetteVet, wow! Thank you for the detail. Would you still believe this to be true even if the headlights were fine before the LED's!

[VetteVet]

I sorta assumed that they worked OK before but you didn't say in your post. The tests were to check the power to the headlights as well as the hesitation. in order to find out where it might be in the circuit.

There isn't really a reason that the LED' s would cause this because they are on a different circuit than the headlights even though the headlight switch controls both circuits. I know several of the guys have installed the LEDs but I have not heard them say they had your problem.
One of the orange wires off the fuse panel goes to the headlight switch, where it connects to the brown wire for the parking and tail lights when the switch is on. See the top two diagrams. The red wire to the light switch connects to the blue wire for the headlights at the same time, but the two circuits do not mesh.
Are both the turn signal and the parking lights LEDs?

[hamjet]

Would it hurt anything if you were to put the orininal flasher back in to see if the headlight problem still exsists?

[heathbirkendahl]

VetteVet, thank you again! I'm going to start with ordering a dimmer switch cheap test.

Hamjet, I did that very test and all goes back to normal and works fine.

[heathbirkendahl]

VetteVet, Did answer one of your questions. The marker lights are not LED. Still a standard bulb. However, I did notice the left marker light is dimmer then then the right one when the headlights are on.

[VetteVet]

The only thing that ties it all together is a poor ground and that may be at the marker light.

Do you have the headlight relay kit installed. It will give your lights more power at idle and it might solve the delay problem as well. Just to be sure, your headlights are not LED right?

[davischevy]

Not my thread, but, Thanks for the schematics VetteVet.

[VetteVet]

Originally Posted by davischevy

Not my thread, but, Thanks for the schematics VetteVet.

You're welcome but I can only take credit for posting them, some one else created them from the factory manuals.

[heathbirkendahl]

VetteVet,

Headlights and the rest of the wiring is all factory at this point. Truck wiring and lights are all factory minus the LED Tail and Parking lights. The LED's are the kind with the bulp end that plugs into the factory socket.

Thanks again for all your help! Truly awesome group of guys on this forum.

Heath