in the dark here??

pro street rich

Registered User
Well I got something that is going to drive me crazy.. I got my 1990 S.C. out from winter storage and I have something going on with the lights...Last year at the end of the season I replaced the headlight switch for this same issue, but because it was the end of the year I never got a chance to make sure it was fixed..
So here is what is going on.. I turn on the lights and everything is fine. Then when you drive for about 30 to 45 minutes the lights will start to flash or go out completely I have played with the switch turning up and down the interior lights and this sometimes helps for a few seconds but that is it.. I have already replaced the headlight switch with no change in the issue?? This is a non auto headlight car...and the car has NEVER been messed with as I have owned it since new??

So does anyone have an idea here?? The car is good for 30 min rides, but after that it is scary to drive at night with it?? any ideas would be great..Remember I did already change out the switch on the dash with a new "oem" Ford one with no help to this issue???......Rich:cool::eek::eek:
 
still no help...

Like I stated I already changed out the headlight switch with no help... There is NOT a MFS on this early bird. This has an old style switch which you putt out and push in on the dash, not on the steering column like those other post talk about.. I did look at the wiring the last time and they did look ok so no burnt wires here..Still looking for a reason.....Rich:confused:
 
All early SCs have the pull-on light switch up on the left side of the cluster/dash. If it has turn signals with wiper controls, pull to flash highs, and 4-way flasher, it has/that is a MFS.

When replacing, be sure to stick w/same color code ...either green or blue. Replacing one style with another can lead to spooky issues.

As part of the debugging process, don't forget the multi-wire ignition switch down on the right side of the steering column, inside the dash...you may have to remove the two-piece plastic bezel around the steering wheel base to see...sometimes they open up and cause issues. New from AZ, etc. should fix it if it is.

Does the car also have fog lights?
 
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Rewire the headlights on a relay. That style switch runs all the current for the headlights through the switch. It overheats, and opens up the contact, causing the lights to shut off. By having the switch only controlling a relay, you will keep the switch from overheating, and as an added bonus, your headlights will be brighter due to having much less wiring that the current has to go through before getting to them.
 
me bad...

The multi function switch is the turn signal switch Rich.

I should have known that, some times this old head is not hitting on all eight... I have been working on a 427 fairlane that has been driving me crazy with everything I am doing to it... Then my daily driver go and acts up.. Thanks for that info....Rich
 
I'm glad this subject came up. I had the same problem a couple of weeks ago. I rarely drive my SC at night but a couple of weeks ago the wife and I went out to dinner. On the way home we turn onto our dark country road and I flick on the high beams. Two min. down the road the lights go out. Scary stuff because these roads are pitch black at night. So I get on the brakes and flick the high beam switch back to low beam and they come back on for a few seconds and then go back out. I'm like ~~~. So I flick the switch back and forth and I get the low beams back on and drive the few min. home nice and slow. So I figure it's the multi function switch and order up a new ford switch from rock auto and install. But I still haven't tried it at night yet. Now I'm wondering if It is fixed.
 
Again, the only long-term fix for this is rewiring the headlights so the switch is only operating a relay instead of running all the current for the lights through the switch.
 
Again, the only long-term fix for this is rewiring the headlights so the switch is only operating a relay instead of running all the current for the lights through the switch.

This - my 93 LX had the same problem. Went through two turn signal switches since I ran the fog lights so much.
 
Wasn't there a recall on this affecting all 89-93's equipped with fogs? The wiring gauge in the headlight harness is too thin and the high resistance causes the "circuit breaker" to trip momentarily and your headlights flicker or go out for a few seconds. The fogs run off of the same circuit. If that's the cause of your issue, when the fogs are on, the problem should become way more prominent. I think this was a safety recall? If that's the case, I think Ford has to replace the harness no matter the age of the car or when the recall was issued.
 
Nevermind, it was the Turbo Coupe and Mustang GT I was thinking of with the harness issue.

The MN-12 birds had a headlight switch recall


Recalls for THUNDERBIRD FORD, FORD MOTOR COMPANY, EXTERIOR LIGHTING:HEADLIGHTS:SWITCH, Oct 12, 1999
A recall was issued on Oct 12, 1999 for THUNDERBIRD FORD, manufactured by FORD MOTOR COMPANY, in response to EXTERIOR LIGHTING:HEADLIGHTS:SWITCH problems. VEHICLE DESCRIPTION: PASSENGER VEHICLES EQUIPPED WITH FOG LIGHTS, IN WHICH THE HEADLIGHTS MAY GO OUT FOR VARIOUS INTERVALS AND WHICH MAY BE PRECEDED BY FLICKERING OR BLINKING AS A RESULT OF THE CIRCUIT BREAKER OPENING.DRIVER'S COULD EXPERIENCE A LOSS OF VISIBILITY, INCREASING THE RISK OF A CRASH.. Follwoing is the summary of corrective actions taken: DEALERS WILL INSTALL A HEADLIGHT SWITCH WHICH INCORPORATES A CIRCUIT BREAKER OF REVISED DESIGN, AND INSTALL A WIRING HARNESS CONNECTOR, IF NEEDED.
FORD RECALL NO. 99S30.OWNER NOTIFICATION BEGAN NOVEMBER 15, 1999. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT FORD AT 1-800-392-3673.ALSO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S AUTO SAFETY HOTLINE AT 1-888-DASH-2-DOT (1-888-327-4236).


Maybe you replaced it with a switch made before the issue was discovered and the switches were revised? Was it a NOS switch?
 
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Funny story here---I can laugh about this now, but it certainly wasn't funny then.

On my 3.8 Mustang, I had noticed that my lights were flickering on and off when the car was shut off. I only noticed this at night, so it's possible that this was going on for some time, if I was only driving the car during the day. Googling this problem, what the cause of the problem seemed to be, was a headlight switch malfunction, where the switch would fail in these cars and the switch would get red hot and would start to melt the harness. I saw that the connector was slightly melted, so I changed out the headlight switch and spliced in the new harness with little difficulty.

The flickering continued, so I figured it must be something else, but i'm not a car electrical expert. I left it be. Fast forward to a month or two later, and I was shopping in a store for a minute or two, when my car alarm went off. That's odd. On the fob, it had the key icon. I walked out, and SMOKE was billowing out of my car. WHOA! A guy that was standing around the car, asked, "is that your car?" I said yes. He said "I just called the fire department". The fire truck was there within a couple of minutes, and they had sprayed the front of the car down. Bizarrely enough, neither they, nor I could figure out where the cause of the fire was. It was coming from the driver's front side, kind of by the battery/ headlight area. After they had left and when we were sure that the fire was out, I checked under the car, and close to the radiator was a little black box that was melted and disformed.

It was the daytime running light module (drm, I believe it is called). If the SC's have this, get this fixed now, because when these things go, it's ugly....and dangerous. If memory serves me correct, the cost of the part and labour was in the $125-$175 range.
 
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