Brake / Reverse lamp voltage issue
Thread Starter
Junior Member
Joined: Jun 2013
Posts: 5
Likes: 0
Brake / Reverse lamp voltage issue
New to the forum. '07 f150 Lariat. First let me say thanks to SSCULLY for the great diagrams and advice he has posted and general good tech post forum wide. It's nice to find a forum with use full info for the DIY guy.
So here's my deal:
2007 F150 Screw.
My turn signals started fast flashing, my back up lights quit and the brake lights got very dim
>Tested circuits showed 10V at Brake/turn and reversing lamp sockets when activated. Tested 12V + to chassis GRD and showed 10V.
>Remote brake light on cab roof works fine
>Replaced the Flasher relay and the flashers are working
>Replaced the Brake position switch just for fun
>Replaced 20amp F10 fuse-it was blown No change
>Checked F14 and F102 as good - have not checked voltage across
Trailer lights work fine in brake and turn mode - I use the 4 pin connector
When I brake I hear a relay clicking in the CJB but I can't identify which one. Maybe the Tow/Reverse lamp relay on the back? The unserviceable one no doubt.
Have not checked DTR or molex connectors from CJB to back of truck
Just noticed this morning that the Mirror is unplugged? Hummm, wonder if previous owner had a problem......
Interestingly the Reverse lights don't work when the trailer is hooked up (it has LED lights) but when I made a temp harness and hooked up 2 35 watt lamps to the turn signal wires on the 4 pin connector the reverse lights come on. Almost sounds like a ground issue.
Any smoking bullets or back to the meter and start pulling connectors?
Thanks
Tim
So here's my deal:
2007 F150 Screw.
My turn signals started fast flashing, my back up lights quit and the brake lights got very dim
>Tested circuits showed 10V at Brake/turn and reversing lamp sockets when activated. Tested 12V + to chassis GRD and showed 10V.
>Remote brake light on cab roof works fine
>Replaced the Flasher relay and the flashers are working
>Replaced the Brake position switch just for fun
>Replaced 20amp F10 fuse-it was blown No change
>Checked F14 and F102 as good - have not checked voltage across
Trailer lights work fine in brake and turn mode - I use the 4 pin connector
When I brake I hear a relay clicking in the CJB but I can't identify which one. Maybe the Tow/Reverse lamp relay on the back? The unserviceable one no doubt.
Have not checked DTR or molex connectors from CJB to back of truck
Just noticed this morning that the Mirror is unplugged? Hummm, wonder if previous owner had a problem......
Interestingly the Reverse lights don't work when the trailer is hooked up (it has LED lights) but when I made a temp harness and hooked up 2 35 watt lamps to the turn signal wires on the 4 pin connector the reverse lights come on. Almost sounds like a ground issue.
Any smoking bullets or back to the meter and start pulling connectors?
Thanks
Tim
Thread Starter
Junior Member
Joined: Jun 2013
Posts: 5
Likes: 0
Well I found the problem. It was the Molex connector under the drivers side door on the chassis frame. Moisture corrosion cause 2 pins to rust and thus a poor connection. I snipped the 2 wires out and made jumpers and now all lights are back to normal. I waterproofed the push connectors with some RTV silicone.
If you have problems with rear lights I'd definitely pull this connection and clean with CRC or similar and then seal the connector. I like the Fluid Film for that. Those connectors look to be splash proof not waterproof and are a problem waiting to happen.
Does anyone have the pinouts for those connectors? It sure would be handy.
Thanks
If you have problems with rear lights I'd definitely pull this connection and clean with CRC or similar and then seal the connector. I like the Fluid Film for that. Those connectors look to be splash proof not waterproof and are a problem waiting to happen.
Does anyone have the pinouts for those connectors? It sure would be handy.
Thanks