help

[jsmoke]

I have an 85.5. My headlights start to flicker on and off after its been on for like 10 min. Is this a harness problem? Also, the speedometer won't move until the car is warmed up in the cold mornings. I can't drive it at night and it's killing me. Help!!

[kiwi]

Let's see/ I had an old mustang where the headlite dimmer on the floor was to blame ( 1966)....Maybe some kind of a short where the "breaker" in the system is dropping the current....
My 2 cents.

[Pat_in_L.A.]

See the light

At the least you most likely have a bad ground.
Trace the ground wires from the headlamp sockets up to the core support where they ground to the unit body. Remove the screws and clean or replace the electrical eyelet connectors. Sand down the area on the support where they make contact. If the problem persists, then replace the headlamp switch and any faulty wiring that leads to the switch. They're not hard to spot, they'll look pretty toasted. If you are able, install an auxiliary headlamp relay to take the load off of the headlamp switch.

[svony]

I agree with the above response... I had the same problem, replaced the headlight switch and it's been fine ever since.

I have no idea why the speedo will only work after the car warms up, the speedo is mechanical so it should move right away. Maybe the gear at the end of the cable is worn/bad.

Good luck.

[GAboySVO]

If someone has put a liquid or simi-liquid lubrication in the cable to stop some noise, It might be freezing or become very thick until things warm up.

I would suggest loosening the cable on both ends so that you can spin it freely. Do this on a afternoon before a cold night. Check it in the morning to see if there is any difference. If it is more difficult to turn in the morning, then you will need to flush the speedo cable with an appropriate solvent, allow it to dry, and properly lubricate it.

You can also check the gear in the tranny for wear at the same time.

[SVOeric]

ummm --- the headlight thing is a known problem.

first thing to do is replace the headlight switch itself.

[Ken Potter]

Related to driving light switch / relay

I have two 85.5's and it is also related to the driving light switch. I'm an original owner on one of them. The dealership replaced the relay on my original and it has had no problems since. I just purchased the second 85.5 back in September. It also shorted out when I had both headlights and driving lights on. The headlights started blinking on and off then the switch literally burned up / smoking / melted. I haven't done anything with it and don't even know if the relay is still available. I'll get back to it at some point. I just don't drive it at night. I had asked for help awhile back but never received any real advice or if there was another fix for this problem...

[SVOeric]

this depends on your circumstances ----

if your headlights are blinking, and you are not smelling things burning, check your wiring. If it is fine, replace the headlught switch, and you will most likely be fine.

if you see the melted switches like ken talks about, there are other fixes for it--

one is installing a new (extra) relay, closer to the battery, so the headlight switch and fog light switch are only used to kick the relay that actually handles all the power. (you may want to seperate them, and use one relay for the headlights, and one for the fogs)
-- the reason this is necessary is Ford used (IMO) wire that was barley capable of handling the amprage to run the lights and fogs.

Once the wire has aged a bit resistance tends to get a bit higher. then this problem can start to show up.

Moving the relay closer to the lights and battery takes the load off the wire running to the switches, takes the load off the switches themselves, and lessens the distance of wire that is under load ( a good thing)

There have been MANY MANY Magazine articles, and internet articles written on how to do this (this process is the same as on any standard mustang)

If you can't find one, let me know. I'm sure I can dig out a magazine with the article in it.

Ken, I thought your issue was fog lights only --Maybe I Just read it wrong?