Chev, 1500P/U, 130,000, V8. The headlights won't come on when the switch is turned. The daytime running lights seem to work fine. I have checked the fuses and they seem to be o.K. I have changed out the light switch but it did not help. I checked the voltage at the headlight plug and found approx. 9VDC. The lights themselves look o.K. And had good continuity.
Need a year for your truck to look up the wiring diagram. Does it have 12 volts at the headlight switch? Is there a headlight relay in the underhood power center?
August, 19, 2007 AT 6:43 PM
I have 1997. There is no relay for the lights in the relay box under the hood, just a 50amp fuse which checks o.K. I have 12volts at the switch. All of the interior lights work along with the dimmer.
I checked the voltage at each position on the connector itself. The connector has a total of 11 terminals with a group of 4 and a group of 7. Two of the group of 4 have black wires which I believe to be neg (-). With the connector oriented with the four terminals on the right I found 12 volts on the far right terminal above the grounds and on position 3 (going from right to left) on the 4 terminals in the group of 7. I also found 12 volts in the middle postion in the group of 3 of 7.
I also checked the voltage for at the bulb connector once again and found 9.4 volts when the running lights were on but zero volts when the switch was turned for headlights.
August, 20, 2007 AT 7:48 AM
Power comes out of the switch and goes through the Daytime Running Lamp Module (behind left side of dash) be sure 12 volts is getting throught that, then it goes through the dimmer switch (hi-low beam) check for 12 volts through that as well, get back to me
August, 20, 2007 AT 9:58 PM
I poked around the steering column looking for the terminal for the headlight dimmer switch and while poking I decided to try the lights and they worked. Needless to say I was puzzled and poked around somemore. I found that if I tilted the steering wheel up and down the lights would go on and off. So, I figure there was a wire grounding out. I thought the wiring harness on the back of the switch assembly was a plug and when trying to pull it out a wire came loose. I didn't really tug on it I think it was loose in the connector and when the wheel was tilted it either made contact or didn't.
It doesn't look like there is a plug back there and if I can't fix that wire I'll have to replace the whole assembly. Of course that looks like a major either way.
August, 21, 2007 AT 7:54 AM
If the wire just came out of the connector, you might be able to fix it by enhancing the locking part of the wire end and reinstalling it back in the connector
August, 21, 2007 AT 9:20 PM
Jack, thanks for the help. I tried to provide some feed back but I don't seem to have the points that the system will take.