1993 F250 7.3 IDI Dash wiring harness issues

[InnovativeAV]

took the whole dash out trying to find out why we were having electrical issues....turns out the guy who owned this before me swapped the cab and left the dash harness from a gas in the truck. so now does anyone know how to modify one to work with the 7.3IDI? or does anyone know where to get one?

Thanks in advance....maybe someday I will get to drive my truck!!!

 

[76ford466]

Im doing a gas to diesel conversion on a 92 myself. What part is not working properly for you? Amazingly most of the wiring is the same for either. I have got all of my sensors to work so far except the wait to start light havnt got to that one yet.

 

[InnovativeAV]

The tach works only with the parking lights and headlights off once you turn them on it dies right out to zero. We are having issues with the windshield wiper motor and the heater controls. Also the transmission has somewhat abrupt shifts. Now I do have the wait to start on the dash so I don't know if they modified it I haven't looked too far into it. Speaking some of these problems out seems that it might be another issue. we are looking into grounds. But we were told by a repair shop who works on diesels all the time that some of the pins in the diesel harness maybe different than the gas harness and that maybe why we are losing certain functions. I wish we could find a schematic for each on the Internet and compare that would be nice!!!


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[franklin2]

It does sound like a grounding problem. Take one side of a jumper cable and clip one end to the battery negative, and clip the other end to a good metal spot on the cab sheetmetal. See if that cures it. My truck has a factory ground clipped from the cab to the frame under the pass side door, and all of them usually have a ground from the firewall to a bellhousing or intake manifold bolt on the engine.

 

[cpdenton]

Best thing I ever did was spend the money for one of these.

All schematics for gas and diesel are in this as well as troubleshooting guides.

http://www.amazon.com/Bronco-F150-F...uum+troubleshooting+manual&pebp=1418951788073

 

[joe f350]

i might have what u need u say u want a dash harness right and cluster

 

[cpdenton]

The ground for both your tach and your interior gauge lights is located to the left of the drivers feet behind the kick panel.

To me, it sounds like the tach is grounding through the instrument lights when the lights are not on. It is finding ground through the bulbs. Apply power to that bulb, and the easy path to ground is lost. Open that kick panel up, and clean the wires connected to the green bolt(if it's still there), there should be a couple wires connected to it. Clean easy wire ring and the metal on the truck cab at that location. Then, go out to where your batteries hook up. On the drivers side battery, there should be a large ground going to the from of the engine, and a smaller wire bolting to the core support. Make sure this is connected good and clean. On the passenger side battery, the ground runs down to the front of the engine, then a small wire runs from the location on the engine over to the frame.

 

[cpdenton]

I just spent some time looking at the instrument cluster pin outs for a 92 model( I would bet it's the same for a 93) and there is little to no difference in the wire locations for gas to diesel. There is an extra ground wire for the gas model dedicated solely to the tach, but if you have a diesel cluster in your truck, that wire is not hooked to anything. The diesel cluster finds ground for the tach through the same wire as the rest of the gauges, which, BTW, is a ground dedicated to gauge only. Lighting is grounded through a separate wire.

 

[InnovativeAV]

This is awesome information. So we took the whole wiring harness out of the truck the firewall inside is completely cleaned we took everything out of it!!!! We started going through some of the wiring and it look like part of the harness that went to the domelight and maybe the seatbelt wires but they wired something in and didn't even come close to colorcode matching the wires. But this wiring harness was actually unplugged and probably for good reason. I still pretty much believe that this is definitely going to be a grounding issue but the mechanic helping me out on this was wondering about the GEM mod on the driver side kick panel. He said he looked it up in their online portal for whoever he works through they have a whole list of stuff that supposedly controls all of the gauges the wipers the heating controls the dash lights instrument lights everything


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[madpogue]

^^^^^ +1 EVTM. Stars align, you can find one on eBay for $20-ish.

 

[franklin2]

This is awesome information. So we took the whole wiring harness out of the truck the firewall inside is completely cleaned we took everything out of it!!!! We started going through some of the wiring and it look like part of the harness that went to the domelight and maybe the seatbelt wires but they wired something in and didn't even come close to colorcode matching the wires. But this wiring harness was actually unplugged and probably for good reason. I still pretty much believe that this is definitely going to be a grounding issue but the mechanic helping me out on this was wondering about the GEM mod on the driver side kick panel. He said he looked it up in their online portal for whoever he works through they have a whole list of stuff that supposedly controls all of the gauges the wipers the heating controls the dash lights instrument lights everything


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93 has a GEM module? If it does, the only thing it has to do with all that stuff is the power feed. It has a accessory delay that lets some of that stuff work for a time period after you take the key out.

 

[IDIoit]

if the truck has the ZF in it, i would buy an aftermarket kit.
if auto, , stick with stock wiring.

 

[InnovativeAV]

Yep he said he did more research on it and the GEM MOD wasn't put in them until 1995. He said in my year the wiper control module which I do know is bad or something just isn't ground into it basically was in place of something like that. Right now I'm going through the whole wiring harness anything that they might've cut or spiced we're putting back the color coding of wiring to where it should be and we are soldering everything and heat shrinking everything before goes back in the truck


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[IDIoit]

when i solder wires, i use a metal crimp to keep the wires together.
makes it easier to solder rather than twisting the wire together.

 

[InnovativeAV]

So replacing the wiper module. Fixed almost everything. One very odd scenario when you turn the heater on the turn signal lights come on very dim turn signal still work when you initiate them the lights just turned on very dim and the illumination Dims. We have cleaned up and put in basically all new grounds and the ground seem to be working sufficient but it seems like something still bleeding a little bit. The headlight switch was new but I think we're going to replace it again and see if that fixes it


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