Hey guys first post. Soo got a 1981 f100 with some wiring fun....... .Anytime the lights are on the reverse lights are on..now i've checked the wiring in the back made sure nothings grounding out back there made it all nice and clean but didn't fix the problem. just kinda curious if anyone has had this problem before and if they have any helpful hints where i should start next ? thanks

 

There should be no connection between these 2 curcuits.

Power to the reverse lights come off the same fuse as the turn signals and only get power when the key is in run. It then goes through a switch (manual or auto) and then to the reverse lights.

Your other lights get power through a separate curcuit that is live all the time...does not need to be in run.

If you have a trailer lighting connection I would check this. Power could have got swapped within that connection. In fact, there was a wire that went to this connection to power reverse lights on a trailer. So if it looks like that harness has been hacked up...that's a good place to start looking.

Do your blinkers work?

 

one blinker works the other one comes on but won't keep blinking

 

just went out and checked again to make sure i was explaining this right. The reverse lights come on anytime the car is in the on position regardless of what gear (4 speed manual) is in so im still thinking ground? but /shrug hoping theres something i just don't know?

 

Ok so you're getting power to that curcuit...that's good.

You have to be getting power to the reverse lights from some other source then.

 

oh ok...that's a different story then .

I would pull the fuse for the blinkers and reverse lights. Then check to make sure that the lights go out. This will confirm that they are wired to the correct curcuit.
If they go out then you have to have an issue with the reverse swich. Which is mounted on the transmission itself.

 

ahhh yess nice headway thanks alot =) gonna test it tomorrow thanks for your quick responses ill update after i test =)

 

Awesome!!! Glad I could help.

The reverse light curcuit is pretty simple so we should be able to get this one.

As for you blinker not blinking. Check all the turn signals on that side. If you have a loose bulb, bad ground or bad socket it may cause what you're describing.

 

I wouldn't have said this a year ago but, if you have a spare flasher try swapping it. Mine did that awhile back, one side wouldn't blink the other would blink slow, and I couldn't figure it out. So just for kicks I swapped out the flasher and it cured the problem. Never seen one do that before but guess there's a first time for everything.

 

alright so the flasher fuse worked all good on that end and the reverse switch i bought they didn't have at pep boys but found it at autozone $50.00 gonna grab it tomorrow and it should fix the problem =) thanks for your input guys really helped

 

$50!!!!! Really??? Holy cow. I had no idea that would be that expensive

 

yeah i was a little taken back to since the pepboys part was 10 dollars....