I, well actually my son has a 91, f250 superduty 4x2 and I have been having problems with several things….1. I can not get the gauges to move…ie; the gas gauge just sits at half no matter if you fill up or switch tanks, the voltage, oil and thermostat gauges don’t move….i was told to look for a gauge voltage regulator which I can not find…I can’t even get the cluster all the way off because of the speedometer cable but when I stick my hand in there I don’t feel anything other than wires…I don't know if the 91's even had a regulator....2. the speedometer bounces around until you get to about 50 mph…I checked the pinion gear in the transmission and all the teeth seemed to be there, but I don’t think the cable and gear really sits right were it is suppose to…I don’t think the retaining clip holds it in and I can’t find any place that sells any thing for it or have anything information for the cluster to help me….so can anybody help me with it ????? the vehicle inspection is about to come up…

Oh! And does anybody know of any aftermarket parts for the 91 that is affordable to a 16 year old….ie; his tail lights are cracked and his headlight lens assemble is dingy yellow, he watches the car show’s like overhauln’ and trucks on spike tv…anyway he wants to be able to fix it up…

Thanks for your time and input

Strongbow

 

Either all your sending units are bad (probably not), or their is some funky wiring with the cluster. Do all the dash lights come on and dim with the dimmer?

The cheapest parts are of course eBay. They have those 'Euro' taillights and new headlights for cheap.

 

Yes the lights come on and dim….i have tried to follow each wire to see if one is shorted but that takes a lot of time…I don’t know if the wipers have been messed with because they only come on high…I don’t know I don’t like following each wire especially under the dash I much rather rewire the whole thing….anyway thank you replying

 

Since all your gauges are not working, try checking the electrical connector at the firewall. Also, have you checked all the fuses?

On the speedometer, you could have a sticking or binding speedometer cable. Trace the cable and check it to be sure it isn't getting pinched. Also, try getting some dry lubricant into the cable.

On the yellowed headllight lense, if it's surface discoloration and they are plastic, try using Meguiar's Clear Plastic Cleaner and Meguiar's Clear Plastic Polish. I couldn't find them at the autoparts store, found them at the boating store. Along with very fine (000) and super fine (0000) steel wool and a lot of elbow grease you can clean these lenses to almost new.

Ron

 

If your wiper delay module goes bad, the wipers only work in the high position. A cheap fix for that is to get a switch for the regular two position wipers. Just remember to remove the delay module or at least disconnect it(It runs ins series between the switch and wiring harness) and leave it in place.

Chris

 

I’ll try them when I get a chance to work on it again. I did get some of the gauges to work, well two. I was working on the amp meter, grounding it and using a constant on hot wire and it worked. So I found a wire that is hot when you turn on the key on from the harness that goes into the cluster on the left side. I then wired it to the amp meter and it worked. Then I scored the oil pressure switch with a screwdriver and hooked it back up. Now the amp meter on the left side works and the oil pressure gauge on the right side works. But the fuel gauge on the right side moved to full and sits there and I found out that there is no sending unit for the coolant temp gauge and the one I bought that was the only one autozone had for the truck didn’t fit, it was too big. So I don’t know what to do from there. If autozone has the wrong size coolant temp sending unit I suspect so will all the other places and maybe even the dealer. Anyway thanks again

 

tenbears,

First, I'd be leary of doing any re-wiring without finding out for certain which wire in the instrument cluster connector goes to the gauge in question. You may end up, at the least, getting a false reading and, at the worst, frying your electrical system. For example, the "hot" wire you found to use for the amp gauge could be tied to the fuel gauge and that may be why it now reads full all the time since you have grounded it through the amp gauge.

What you did prove using the constant hot wire and ground was that the amp gauge itself was good; and, therefore, it wasn't working due to some other problem (open wiring or bad alternator) and you need to look elsewhere to fix the problem, not just try to re-wire around it.

Secondly, I'm not familiar with the engines on the 91 F250's, but my 92 Aerostar 3.0L engine has two separate engine coolant temperature sensors. One is for the EEC computer to use and is a multiwire sensor; and the other is used for the engine temperature gauge and is a single wire grounded sensor. On later years and different model engines, the multiwire sensor was used to do dual duty and provided signals for both the EEC computer and the gauge.

BTW, did these problems just spring up, or did your son purchase the truck like this. Also, has there been an engine change and could the wiring harness have been connected incorrectly? or the wrong harness used?

Just a thought.

Ron