uwvid

Hi.

I have a problem where the lamp-out alarm triggers when the trailer plug is connected (7-pin), it usually only triggers when I press the brake, or activate the turn signals. If I press the brake repeatedly, the alarm triggers repeatedly.

- If nothing is connected to the trailer plug, there is no alarm.
- The lamp-out light stays out for the most part or lights for a split second.
- Changed the 7-pin trailer plug, still an issue.
- Checked all bulbs on tail lights, and changed a couple. Issue still there.
- Checked all fuses.
- Removed and cleaned the FCM.
- Measured resistance on the tail light circuit board, about 0.02.
- Tested with different trailers, same problem.

The fog light (blue) is not connected on the trailer plug. Is this likely to cause this issue?

saggonwaggon91

There shouldn't be a fog light wire at the trailer plug. Be sure to check all grounds in and around the trailer plug

gcssr

The Blue is usually trailer brakes, check and see what color wire is connected, you can test trailer brakes by applying a test wire to the pins , be sure to ground the trailer but blue goes to brakes

gcssr

https://www.etrailer.com/faq-wiring.aspx see the chart here.

uwvid

Thanks guys.

It's now clear what the issue is. We have the same coloured wires here in Norway, but on our connectors it's :

white - ground
yellow - left blinker
green - right blinker
blue - free or rear fog lights
brown - tail light right side
black - tail light left side
red - stop / brake light

I could rewire everything, but as the car has passed 250 000 miles, I'll probably just disassemble the instrument cluster and desolder the alarm buzzer. All the lights on trailers are working, just the alarm is going crazy.

gcssr

On our's the tail lights, both use the brown wire, the stop/turn are combined, L/ yellow, R/ green, see on wiring diagram;;;;;;; Also U do not have brakes wired in;

gcssr

U could. on trailer side, cut the red don't connect to anything, cut black wire and connect to and with the brown wire, this should eliminate, your problem no more light or dining, try;;;
the brake/stop will work as they do on the truck, left turn, right stop and right turn left stop;;;

uwvid

I ended up removing and disassembling the instrument cluster (which was surprisingly easy), and then desoldering the alarm buzzer from the circuit board. All the lights on the trailer / car is working so the only real issue was the nagging lamp-out alarm.

This also allowed me to check the instrument panel lights as I knew some of them were out. Turned out only 1 out of 11 was working. I had a couple laying around, and have ordered some more from eBay.