Hello XXXXXXXXXXX ,
Thanks for visiting us Technicians here at Just Answer. I will do all I can to answer your question fully and understandable. If you need more assistance on this matter please just hit reply and do so, you can even reply after hitting accept. If this has solved or helped you understand the fix then my efforts can only be rewarded by hitting the GREEN ACCEPT BUTTON. I strive to maintain good feedback so do reply with any form of results.
Thanks Chris
______________________________________________________________________
I feel you have a wire with resistance or a faulty RAP module or the headlamp switch itself is at fault for this concern. Here is a short test you need to perform.
Ok
where are these modules located?
The RAP/CSM module under the left side of the dash.
ok
where is the light sensor amp?
Sorry about that. You pry off the cover on the top of the dash and then unplug the sensor which is on top of the dash.
let me try this and see if it works,
i printed them out and did step by step, why a short looks bad
According to the resistance results you have a concern on this wire if the test is was done correct. The CSM/RAP should not be suppling a ground to the LG/YE when you want the lights off.
Here are some more tests to do
let me try this,
Chris,
question, I have put everything back the way it was except for the park lamp relay and all is working, the auto sensor works turns all lights on and off, the light switch also works in all modes, why would this work without he relay plugged in??
I have not heard back from you, so I assume you are needing more assistance on this matter, if so please do reply so I can finish this question. My goal is to have nothing but satisfied customers.
Thanks Hope to hear from you soon, Chris
Hello Chris,
well it turns out I was told the wrong info (not by you) the relay I was told "parking lamp relay" is not for the parking lamps, relay R201 is for towing if you turn the lights on with R201 in circuit, the parking lights will stay on till you unplug the relay (R201).
What does this relay do, and why do I need it, the trailer lights work fine without them in (both relays for towing, R201, R203)
The parking lamp trailer tow relay is for the park lamps on the trailer. The trucks park lamps signal the relay to turn on so the trailer gets its on powered park lamps so it does not overload the truck wiring and fuse and so there is not a complete failure when there are shorted wires on a towed trailer. Sounds like you have a faulty trailer tow park lamp relay now.
Hi Chris,
When we started to diagnose this I mentioned that the relay was changed, (R201) is new. The guys truck came from the fac with the hitch and wiring installed, so I don't think it is a wiring problem, but all lights work fine with no relay(s) R201, R203 installed.
On your schematic you sent me asking to check the resistance on the relay for the parking lamps does not apply here then, is there another test to see if there is a problem with the factory tow wires from the fuse box under the hood to the hitch?
Ford Technician
Ford trained Tech. Trans, X-fer Case, Steering & Suspension & Brakes, Engine, Electrical
Is it possable that the wire harness going to the trailer connector is grounded somewhere?
Thanx for the help.