93 Ford F350 diesel - My headlights,turn signals,brake lights and back up lights all work fine, but lost taillights and clearance lights(rear wheels and roof). I checked the fuses and none blown. Also tried swapping relay, no luck. Any ideas where to start troubleshooting further? Thanks.

 

How about the front marker lights? They are on the same circuit as the rest of the non-functioning units. If they aren't working either, I would first check the fuse again. Pull the fuse out and turn the headlight switch on one click (the one that activates only the tail and marker lights) and test the slots where the fuse inserts to see if you are actually getting power from the headlight switch to the marker light circuit. If not, the wire from the headlight switch, the switch itself, or the fuse block has a problem.

 

about 8 yrs ago I had to splice wires when replacing switch. The marker light wire had come undone.

 

OK - I don't have one of these beasts but I do have the '93 Ford books, including the Electrical Troubleshooting book. Question - do your rear license plate lights work? I ask this because the license lights are fed the same way as the rear tail lights. We'll assume this is all one problem. It does not appear to be a ground problem because the cab lights and the rear lights use different grounds. Also the rear brake lights use the same grounds as the rear tail lights. The rear marker lights do all use the same ground. The only place the circuits you mention are common is in a splice (S213) that feeds park light power to the front marker lamps, the rear marker lamp/trailer marker lamp relay coil, the warning chime, rear tail lights and license light, and the cab marker lights. If this is one problem it probably is in that splice. The splice location, per the book, is in the "main harness near the T/O to the warning chime module". The warning chime is located above the ashtray.


The chances of part of a splice failing are slim, if you haven't been messing with or around the main under dash harness. The first thing I would do is determine if this is all one problem. Check for voltage presence at the lights. If some of them have voltage and others don't, it is problably two problems.

Let us know what you find out, when you know more it may lead to other thoughts that come to mind. The lighting on your diesel F-350 is the same as a gas F-350. There are a number of things different on the harness between a gas and diesel but they are confined to engine, fuel system and gauges. The lighting appears to be the same.

One more question - have any modifications been perfomed on or around the wiring harness of this truck?

 

problem solved - one of the 8 year old splices came loose, reconnected and all is fine.

 

I have a 2002 F250 with 38k miles - I have no park lights, chime doesn't work when lights left on with key off and door opened and no chime when key in igntion when door is opened. Previous owner installed an aftermarket door lock remote which activated the park lights when remote is used to lock/unlock the power locks which this doesn't happen now nor lock/unlock the power locks.
No for sure about rear license plate light.

I have checked all fuses and bulbs and all good. Ford house wants $89 for head light switch and they also indicated another part might be out for much more $$$.....

Any ideals????

Thanks,
Mike

 

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Feel free to share the contest with your friends.


Thank You

Dave Jabas

 

I would find this gizmo, and see if you can take it out.