welcome to FTE... Depending on what wiring you lost to the mice/rats you can probably be safe pulling a harness from another 87/88-90 EFI 302 or 351w with XL or XLT package b/c it has the AC wires for the compressor. Keep in mind EFI was new in 87-88 so the wiring for the SD EFI systems weren't integrated into the truck harness fully until 89-90...
1988 F150 to 1990 F250 Transm./transfer case wire hookup
I am trying to transfer a 88 F150 wiring and fuel system onto a 1990 F250 4X4 chasis and drive train with a 5 speed stick which was wrecked. I am also transfering the 4.9L out of the F150 to replace the 351W in the F250. Everything seems to match up except some of the wiring. I am trying to find the electrical wire that will attach the tranny and transfer case to the wiring harness of my 88's 150 2wd wiring harness. The hookups are not the same as on the 90's 4X4 wiring harness connections with the 351W. The wire operates the backup lights and dash lights when it is in 4 wheel drive. Do you know what will work?
Last edited by ps71mustanger; 07-03-2011 at 07:31 PM.
I'm not sure I follow what you are trying to do... IS there 3 trucks? how are they set up? what are you trying to rob from one to make the other work? be a little more clear about what you are trying to do/accomplish... Please...
I don't have the oem wiring pics here at work... You'll need the wiring diagrams for all 3? trucks so you can match the wires... Or you'll have to power the wires with 12v current to find the back up light wire. Or if someone else on here understands what is going on better than I and have the right diagrams????
I have 2 trucks. A 1988 F150 2wd with a 4.9L 5speed stick. The other truck is a 1990 F250 4X4 with a 351W 5speed stick. (Or 4 speed w/overdrive)
I am wanting to transfer the body of the 1988 F150 onto the frame and drive train of the F250. I have already removed the body off the F250 as it was wrecked in the drivers side and had major rust and has been scrapped.
I am also transfering all the wiring, fuel tanks and lines from the F150. I am also removing the 351W and putting the inline 6 in it's place.
So basically it will be my 1988 truck on a 1990 frame and drive train.
Everything should change over just fine. The only thing that I don't know about is the wiring that connects the transmission and transfer case to the main wiring harness. (for the back up lights and 4X4 dash lights I presume)
The F250 has 2 connectors to the main wiring harness from the transmission and transfer case, but they are not the same type of connector as the F150.
On the F150, it has only a single connector from the transmission. I cannot find another open connector for the transfer case unless it was set up differently for that year and has only one connector.
I don't know if a 1988 F150 4X4 from a junk yard would have the connecting wire that I am looking.
The first diagram is great for the 1990. The other ones are for a 88 truck with electronic shift. Mine has standard lockouts, not electric. Mine also has a 5 speed standard transmisson and 4.9L engine if that makes any difference.
The wire hookup to the transmission and transfer case is the only issue I'm trying to resolve at this point.
I want to see how the 1988 F150 2wd transmisssion wire hookup compares to the same year with the 4X4 transfer case added. I need to see how they are different and if I can use my 2wd wiring and adapt it to a 4X4 setup. I could use the 1990's wiring from the transm. and transfer case and splice into the 88's if I could figure how to do it. The 1990 seems to have a completely different wire set up then the 88. I didn't figure there would be that much difference for 2 years since the body and everything else is the same. If you could find the diagram for the 1988 2wd, and the 1988 with 4 wheel drive without the electronic shift module that would be great.