1999 Windstar brake lights not working - Page 2

philkb · 12-05-2007, 08:07 PM

There is a lamp outage module that also has circuitry that puts a ground on the appropriate lamp so as to light it. That is why there is special wiring for a trailer hitch so as to cause 12v to be applied to the trailer lamps, which are grounded on their other terminals. This is the "brain" being referred to. So, be very careful when poking around in the lamp circuits. My Eagle Premier has the same setup. There may be a problem with your lamp module.

Flyingjackal456 · 12-06-2007, 04:13 PM

1.) no... negative is ground, anything metal on you car (other than the positive wires) is ground. Therefore having a relay for negative would be pointless.

2.) Obviously the wires

, have you done any recent work on the van (since the issue started)? Did you kick up any big stones on the road, hit something (accident), etc. Anything can destroy the wiring. Take a look in any areas or the van that you recently worked on. Also the trailer lighting kit (if equipped) it is a black box next to the emergency jack with a bunch of colored wires coming out of it. Try to wiggle the wires near the fixtures, if you happen to find a weak or broken connection, fix it.

AHHH, Ford's notorius random bad grounds....Anyway, if I'm reading this correctly, the brake lights are not getting ground (negative) There should be no relay for ground and if you're sure that's the only problem, just drill a hole, and mount a wire on any bare metal of van (please don't drill the quarter panels). Run those wire(s) up to each light and ground each one. Then the issue should be fixed.

philkb · 12-07-2007, 08:31 AM

The lamps are wired with battery voltage on one side so that the lamp outage module can "see" whether a lamp is good or bad. If the module doesn't see that battery voltage due to a burned out lamp, it sends a message to the monitor up front. Thus, the module side of the lamp has to go to ground in order to light. I've never had a module apart so I don't know if the ground is supplied by a relay or power transistor, but it must be one or the other. I believe the module is located behind the right rear inside panel. You can then check wiring from the module to the lamps and see if they're OK. If they're good, then you need to did deeper into the wiring, but there are a lot of other control modules on the van so there may not be a direct connection from your brake switch to the module. If you are not getting a lamp out message, and the center light works, it sure seems like a module issue. If the wiring from the lamps to the module were faulty you would also get a lamp out message.

homedepot · 12-07-2007, 09:46 AM

First, thank you guys for your comments

Here is what I have found out so far. So far the wiring route goes from battery/relay to the fuse, from there to the brake pedal switch and from there it joins the "main" harness. I took apart the panel that surronds the hood pull latch to the left of the brake pedal. In this section I found the harness coming down from behind the dashboard and identified the cable coming from the switch. In this section it splits in two. It carries +12v.

I followed the harness and I could not see any sensors/computer/modules when lifting the carpet in front of the driver's seat. With center an rear seats removed, I lifted the carpet and through the holes in the carpet for the seats to meet their locking bases I saw the harness running from front to back in a plastic moulding through the center of the car where it continues to a point between the rear wheels where it splits in half. Each half goes to each rear corner. One is a little fatter which I believe it is due to the wires going to the rear door/gate.

The wires changes color and I can not determine where, but I think is near the driver's seat.

With that said, and not wanting to disasamble 1/2 a car, I ran a wire I spliced onto to wire coming from the brake switch and ran it all the way to the driver's side rear quarter behind the stop light. Added a generic relay and connected the wire I added from the brake pedal wire to the +12v, I grounded the oposite pin on the relay and grounded the power source. The last pin, I ran a wire to both tail brake lights. IT WORKS GREAT!!!.

It does not make sense, but as I said before, the lightbulb socket +12v is always hot and the light-outage module sends the -12v to close the circuit.

Philkb is right in how these lights work. My light outage module must be bad, but I have no clue where it is. I lost the right breake light first, 4 months later the left, and the license plate lights sometime in the last 6 months. Too much coincidence, it has to be that module. If anyone finds out where it is, I would love to know so I can fiddle with it or replace it and bring all the wiring back to stock.

With that done, I now need to fix the license plate lights, then the ABS brake light issue and then the ckeck engine light.

Hey why fix all the dashbord lights, it looks so Christmasy!!!

I would appreciate in further thoughts on fixing the light outage module.

Thanks a bunch.

Alex.

philkb · 12-07-2007, 08:27 PM

I did some checking and the module in question is called the rear electronic module and it is behind the right rear panel. It will be marked indicating that it is programmable. It's a fairly large box, about 8 or 9 inches square or so. If you open it, then you will know if there are relays inside or if it's all transistors. hopefully, water hasn't found it's way into the box and damaged circuits inside. the proof of the module being the culprit is in the fact that the center brake lamp is also grounded from the module as well as the signal from the brake switch is fed into the module. With luck, and a little electrical or electronic skills, you may be able to repair it. I would guess that it's probably quite expensive to replace unless you can get one from a junk yard.

homedepot · 12-10-2007, 07:36 AM

Philkb, thanks for the info I will try looking into it, but I am afraid that is what the mechanic said would cost $800 and the local ford dealer had no clue of it's existence. They could only pull the info on it and price +- $800 but the parts inventory did not even had an estimated delivery time because the didn't have any. Is that legal?

To answer Flyingjackal 456 elarlier question, the car has not been in an accident other than a rear ending 3 years ago which resulted in the replacement of the rear bumper and tail gate, which is ironic being the only brake light that still works. The license plate light does not work though but it did after the repairs were done.

When I have time, I will look into that module and see if I can fix it. I used to fix compouters 15 years ago so I feel confident about doing work on electronic boards.

Well I am off to digging a little more on the other problem the Windstar has I didn't mention which came up last night: the O/D light blinks when the transmition pulls out of O/D when going up hill after it has warmed up. But that is another episode.

Flyingjackal456 · 12-10-2007, 03:24 PM

Well sometimes rear-ends (or any accident) can cause an unknown issue, and it later shows up. It's possible that the read ending caused a hole in the floorboards, causing water to come up into the module. Good luck on the electronics check / rebuild.

...that other episode might be either, low transmission fluid, or signs of a tranny rebuild coming up.

joshieboy · 12-23-2007, 01:33 PM

I had the same problem with my windstar and found out that the rear control module lost its ground, was able to find it at my local ford dealership for $250 and they had to program it for another $50. hope this helps

RacerHog · 12-23-2007, 09:53 PM

I think i would have went for the turn signal switch or the module....How ever I think you need the GSA Ford scan tool to check that?????

daveck2 · 03-06-2008, 08:54 AM

I took my 2001 SEL to the dealer because I had 12v going to the bulbs and had no way to test the REM or it's signal to the negative side. The dealer hooked it up to their computer and found a voltage drop at the bulb sockets. They replaced both sockets and $171 later I was out the door. I think I didn't suspect the sockets because the both went out at the same time and I assumed it was the REM since so many people were having issue with this module. Hope this helps out the next guy.