I just bought a 93 f-150 real cheap and it has 2 problems. The headlights go out for about 3-4 minutes and then stay on for about 3-4 minutes. I pulled 1 of the large fuses under the hood and when I pulled it the headlites went out so I assume that fuse controls the headlights. But Im not sure why they go on and off. Next problem: The automatic transmission kinda slips like a standard transmission. It takes off fine without slipping and its shifts fine without slipping. The problem is when you are moving in 3rd gear and accelerate even moderately it kinda slips or shudders just like a standard shift does when the clutch is weak. If you accelerate very very gradually it does not do it. Also you can accelerate hard from a complete stop and it does not do it either, only when you are moving. Turning of the EOD button does not make any difference. It was 2-3 quarts low on fluid when I bought it so I added a quart of lucas and 2 quarts of fluid to bring it up to full. I have a very small investment in the truck and the 4.9 inline 6 runs like a sewing machine. I would appreciate any info, thanks.

 

Not sure what to tell you about the lights. The tranny issue does sound like torque converter shudder. I would start by dumping the transmission fluid.
Do not flush the transmission!
Drop the pan, drain fluid. Then rotate engine until TQ drain plug is visible through access hole(hopefully blocked by rubber plug on bottom front of bell housing). Drain TQ as well....it holds alot of fluid and needs to be drained to properly remove the old and likely bad fluid or wrong fluid. Reinstall the TQ drain plug and replace pan gasket and if need be tranny filter. Refill fluid and rotate engine a couple of time to refill torque converter. Recheck fluid levels and top off as necessary. Be sure to use the proper fluid.
All the best. Hope it is nothing more than a simple fix!

 

Not sure what the problem with your lights is ,but I would figure that you have A loose connection either in your harness leading to your output power...or it my be in the fuse box under your as you mentioned before....I would suggest you remove the fuses and relays one at A time...looking for loose ones....when you put them back add dialectric grease..(not sure if that's spelled right) That should allow positive connection....
Rick...
1992 F150 4X4 I-6.....

 

Ford headlight switches have a relay in them that trips when overheated them automatically resets itself until it trips again.

Keeps you from having NO headlights at all.

 

You learn something new everyday......I had never heard of that.

 

I am giving an update on the transmission problem which was actually a torque converter shudder. I seem to have it fixed. I had read about a product called Dr Tranny's shudder fix that is a Lubeguard product and is sold at Napa. It is a friction modifier. Every review I read about it was positive. I spent $13.00 on 2 tubes and poured them in and drove the truck about 15 miles and in the last 7 or 8 miles the shudder stopped 100%. That makes me feel better thinking that tranny is not neccesaily toast. I didn't wanna spend for all that new tranny fluid and filter just find out it didn't fix the problem. So now I will drop the pan and drain the torque converter and drain the tranny lines and install all new fluid and a new tranny cooler and probably reinstall the friction modifier again. If anybody has anything to add that I should do when the pan is down please chime in. I'm still tryin to figure the headlight problems. Also it keeps blowin fuses for the tailights. Thanks for all the help.

 

I wanted to give a quick update. I finally got around to changing the fluid in the pan and TC and filter and the tranny is 100% perfect. Thanks.

 

you might have a short in the wire