I just bought this 89 Ford Van E150
It has a 302 with auto tran.
My or it's problem is with the wiring, I think. When I step on the break pedal
all the runnng lights come on. The brakelight element does not light up only the tail lights light up. The turn signals work properly.
Anyone have an idea. I think what I need is a wiring diagram, so I can start tracing wires
Thanks in advance ---

 

Here's a wiring diagram. What you are concerned with is in the lower right corner.

http://www.autozone.com/images/cds/g...3d801775b3.gif

What I would do first is take the brake/turn bulbs out of the rear sockets, both sides. Then see if the running lights come on when you step on the brake.

If the rest of the running lights do not come on, then you may have a bad ground or bad connection in the rear sockets.

This diagram shows a good illustration of what can happen when you lose the ground connection in the socket or on the body. You will notice the brown wired tied to each light. The brown is the running light circuit. If voltage comes down the other wire for the brakes, goes through the filament, but has no ground, it will travel backwards up the brown wire and turn the running lamps on.

This is just one senario that commonly happens. You may have some other problem causing this, though the only thing that comes to mind is a previous owner messing with wires. If you find out anything else, report back and we may be able to help.

 

Thanks Dave
I will try that in the morning and get back to you.

Bill

 

Also look at the filaments of the bulbs that you take out and see if one of the bulb filament is touching the other. I have run into this a lot.

 

Nuts, they still light up.
I removed the bulbs and checked to see if the filaments were touching ( they were not )
then stepped on the brake pedal. The running lights still light up.
Now, I guess I need to decide on the best place to start tracing wires.
Any suggestions would be a big help.--THANKS
Bill

 

If somebody has added a trailer plug, check the wiring to it and then inside the plug. This is another very common place for this kind of trouble.

 

That crossed my mind and was one of the first things I did. I disconnected it completely
to do away with that possability.

 

This print might be of some good to you.

http://www.autozone.com/images/cds/gif/large/0900823d80...23d801775b5.gif

 

Thanks tho I already had it.
New discovery--it seems somebody took the hazard flasher and put it in the turn signal socket. I don't know if this is a problem or not but the owner's manual says that the turn signal flasher is blue and the hazard flasher is silver. The difference in color tells me they are different. I could be wrong.

 

Somewhere the brake light wire is getting mixed up with the brown running light wire. The brown wire runs all over the van, so it might be hopeless to trace it that way. I think the easiest way would be to follow the brake wire.

The brake wire leaves the pedal switch and goes up the steering column. It then gets mixed into the turnsignal switch, and then leaves the column as two wires, right rear and left rear. These run out of the column, and toward the rear. In a truck they run along the frame, but in a van they may run down the driver's side kick panel, and under the door sill plate in the interior.

I would start in the rear. You already unplugged the bulbs, and the running lights still light. I would follow the wire harness down till you possibly found a main plug. Unplug this and try the test again. Work your way up front till you unplug a part of the harness that makes the problem go away. Inspect the wires very carefully. The brown and the brake lights are bundled together, so if anything got hot and melted, they could be touching.

 

Ok, I found a plugs that disconnect the right and left taillight sockets. I unplugged them
separately and did the test. The rest of the running lights light up when I step on the brake pedal. The wires go into a heavy plastic shield from there all the way forward.
Wires look good up to the shield.
I installed a new flasher into the back of the fuse block. (hazard flasher) And the hazard flights flash and so do the running lights.
Now since both flashers feed power into the multifuncion switch, and both turn signal
and brake get their power from the multifuncion switch could the problem be in there?

Bill

 

No, it can not be the multifuncion switch, the power for the running lights does not go through the multifuncion switch.

 

Nuts, I thought I was on to something, I guess I know just enought about this stuff to get myself into trouble.

 

**Problem Solved**
Found the connection between the running lights and the brake lights. Actually it was the hazard lights.
Someone wired them together up under the hood,I guess because there were no brake lights. Broke that connection and put in a new turn signal switch and everything works
like it is supposed to.

THANKS everyone for all the input !!!!!