Bringing this back because I'm starting to have an issue again. I checked all the grounds they all seem fine. I ended up replacing the dimmer relay (under the steering colum) and I had my lights back no problem. That lasted about a month and then one night I was driving and hit a bump all my lights went out again. Now everytime I put a new relay in it lasts about 2 minutes and then I lose the lights again. Once again no blown fuses or anything. I have no idea where to go from here.
It sounds like you got a loose connection or a Break in a wire "somewhere". The "somewhere" is the tricky part to find. If you have already looked at a schematic and checked the physical ends of each wire run
, it may be time to "try" and track the wiring harness. Another area to consider is the Twi-Light Sentinel Box located behind the Right Side Kick Panel. There are also grounds mounted there and the Box itself is known to have some cold Solder joints. I believe the HL's work thru this box even if the TLS switch is turned off.
When checking the Wiring harness, pay close attention to the connection points. You may want to try and Bypass the Twi-Light Sentinel system altogether by bypassing the 2 Male/Female plug connectors near the base of the steering column. I believe they are white and Black Connector ends. If you look at the "Adding Twi-Light Sentinel" thread, you will see the 2 sets of plugs I'm talking about and you pretty much end up with 1 Male/Female plug to essentially remove the Twi-Light Sentinel Harness and just operate your lights thru the HL Switch.
While following along with your schematic and if you can, unplug each connector you come across in the HL Harness and check each connector point closely for any kind of burnt or discolored connections. For the longest time in a 04 Grand Prix, we had a radio whine issue that would happen when we hit bumps or used the horn. If I hit the Dash Pad area, it would stop for a while or get worse, so the problem was obviously in the dash area somewhere. Checked the schematic and pulled the radio and the connectors looked good there.
What the schematic didn't show was this sub-harness connector that I found near the ashtray only while physically tracing the wiring harness back from the Radio. The 1st pic shows the connector I found and in the 2nd pic you can see burnt mark on the top/2nd from the left pin. Tightened up in this connector and the problem was instantly fixed. Point is, I would have never found it unless I traced the harness and unplugged and looked at the connector. You could have something similar going on or a loose/cold solder joint somewhere OR a loose ground. MAybe try to wiggle wires as you test the circuit to see if you can pinpoint the area. Good Luck..