Flashing Headlight/Check Engine Light

tattoo

Registered User
Hey Guys,
I have tryed the search button and i can't seem to find what i'm looking for.This morning i traveled the hwy for 15 mins at normal hwy speed,exited and stopped at a light and noticed my headlights flashing and then my check engine light came on for about 20 seconds and went out.I was running all my lights including my driving lights,heater and audio.My headlight/fog lights have been re-wired so the switch doesnt heat up.My Alt was rebuilt 2 months ago.Coming home driving the same distance and speed i had no problems..Ideas?

I have already checked my connections and voltages with car running and not running.My battery sits at 12.5 vdc and 14.7vdc with the car running.

Thanks, Ed
 
The flashing headlights could be due to an overheating headlight switch, but the combination of problems seems odd. I wonder if your rebuilt alternator is a little goofy? Was it particularly cold or hot when you drove?
 
Thanks for the reply.Im not sure about the H/L switch, i'm running my driving lights on a seprate relay.I guess age could be a factor.My alt seems fine,seems to be charging ok.Temp this morning was around 45
 
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Did you experience a stumble in the motor when the check engine light came on, or was the audio too loud to hear? What do you mean by flashing headlights? rapid on of, or just cycling like brighter, dimmer, brighter, dimmer.

My gut says a voltage problem. Since it normally seems to be doing well, I'd check the quality of the connections on the alt and battery. Make sure nothing is loose.
 
Thanks for the inputs guys.My audio was playing at a good level,but high enough i couldn't hear if the motor stumbled.As far as my headlights flashing they were flickering on/off.I haven't looked to close at the connections yet i did the ole twist and turn to see if they were tight but that was it.Ignition switch?...If you mean the metal and plastic one with the harness plugged into it than yes it was changed out last summer.

What in depth tests can i put my Alt and charging systems through with a multi-meter?.

Thanks again,
Ed.
 
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Even if the terminals on the battery are tight, they could still have corrosion inbetween. Test for resistance between the outside terminal and the inside. It should be 0 resistance, total continuity. If any resistance shows up, take them off and clean them. That is a great first step before you do any additional testing.
 
I'll vote for headlight switch or a poor connection between the original headlight power wire and the relay.

David
 
Full test procedure for alternator in case you have low charging problem :

First, confirm battery connections are good, all connections and the battery posts are clean, and all connections are tight. Measure ground resistance between the block and battery to ensure good connection

2. Based on what you have siad, oyu have already done preliminary steps to ensur the alt is charging. The next step is to check over/unde voltage. To do a load test follow these steps:

Start engine, turn blower motor on high, turn on high beam headlights. Increase engine speed to 2000 RPM and check the voltage. The voltage should be a minimum of .5v above the base battery voltage and a maximum of 2v over the base voltage.

3. If it's in range, the alt is good, if not, there are more detailed tests to perform depending on whether you are over or under.
 
Had the same problem with my 92 when running the fog lights Ford has a recall on switches just go to the for web site and punch in your VIN# and see if your car comes up mine did and they put a new one in for free
 
Thanks Guys,
I guess i know how im spending part of my Easter weekend....

Thanks Again,Ed.
 
Yeah, flickering lights almost for sure is gonna be a problem at the light switch. A bad alt problem wouldn't flicker like that and let the car keep running.

But you should check the charging system just for good measure while you're at it.
 
Does anyone know how to rewire the fog lights to a different source so that it doesn't burn the headlight switch down? I followed the instructions from here: http://www.sccoa.com/articles/foglights.php
By doing what this says, the fogs should come on when the ignition comes on, and shouldn't be on the same switch as the headlights anymore. When I did it on my car, instead of the fog lights coming on with the ignition, the headlights did, and I couldn't get fog lights on at all. Anyone have any ideas?
 
Hmm, those instructions are kind of vague. What I would do is to just install a relay so that the trigger side is in line with the fog light switch in the center console. Then I would run a new power wire to the power side of the relay and then on to the foglights. Then hook the ground wire up to a chassis ground or the battery. I figure that it doesn't really matter if the power wire is always hot or switched with the ignition, because your headlights are always hot. So you could take it from the ignition switch or from a fuse box.
 
I'm not much of an electrical guy, so a lot of that doesn't make sense to me. I followed those instructions, (the ones in my previous post,) because it sounded like a much easier way for me to do it, rather than all of the other ways I had read about.
 
Ok, I re-read the instructions that you posted, and they do appear to make sense. I know that, in stock form, the fog lights do not come on unless the low beam headlights are on. Could it be that the fogs are grounded through the headlight switch? If so, you may have to run a separate ground wire as well.
 
So are you saying that if I cut the ground wire where it connects to the fog light switch under the console, and take it where it comes out of the switch and grounded that somewhere, that it might work?
 
Yes, maybe. You might want to just rig up something to test first before you go cutting and soldering.
 
Don't forget that the 'flickering headlight' problem can be the headlight switch (Ford recall) and/or damaged wiring in the multi-function switch due to over heated wiring. You'd think Ford would have solved the problem by now, but the same thing just happened on my 2001 Mazda B3000 (Ford Ranger) pick-up. When I had the headlights and fog lights on together I got smoke from under the steering wheel cluster - the wiring was overloaded going to the multi-function switch and the insulation was melting. Got a replacement harness ok for $25 (discount) after going through 10,000 wiring diagrams at the Ford dealer.
 
Out of the 3 wires to the switch, do you know which one is the ground wire? I think that the blue one was the power wire, then there was a black one, and another one. One is the switch wire, and one is the ground wire. My guess would be that the black one is the ground wire, but I don't know. How could I test to see which one it is?
 
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