Electrical Hopefully My Last Cry For Help. (multifunction Switch Problem)

Discussion in 'Fox 5.0 Mustang Tech' started by MikeUrban, Sep 4, 2013.

  1. Hey guys, me again. I'm finally tackling my wiring nightmare:

    2013-07-23 15.03.35.jpg

    So, the car started as a 91 2.3. It was stripped of all wiring, and is now a 5.0 and using the engine and dash harness from an 88 gt. The steering wheel as you can see, is original to the car. I plugged everything in, headlights, corner markers, and hazards work, as do the brake lights and the reverse lights. However, turn signals are dead and so are the high beams. I assume this means there is a wiring difference between the two steering wheel styles. To make my question short, are there any diagrams I can reference to get this thing right? Thank you all again for all the help you've given me. I'll be sure to make a mini build thread when it's done to show everything I've done.
  2. MikeUrban likes this.
  3. Best website ever, but I looked through it all and only found the horn wiring.
  4. A-fckin-men!
  5. It's really not as bad as it looks. Everything is plugged into where it's supposed to go so everything is functional (except this friggin multifunction switch or whatever). As soon as i get that figured out I'll put my dash in and get the whole car finished up so I can drive it! So excited.
  6. get teh multi swtich from an 88?
  7. They're physically different, you can't just interchange them.. I was able to plug the harness in though. I just need a diagram showing an 88's pin out and a 90-93's pin out. I can re pin from there no problem.
  8. Might as well change that 85mph speedo and heater core while it's out :shrug:
  9. Heater core was done last week.. I like my 85 speedo, no need to know how fast you're going if you're over 80mph anyway. That's what time slips are for.
  10. I like the needle gauge at 11 o'clock to 12 o'clock position when I'm on the hwy :shrug:
    MikeUrban likes this.
  11. Okay! So now this is getting interesting :O I remembered I had hacked the connectors off of a 93 and bagged them last time I was at the junkyard. So here it goes, comparison of 90's connectors (cut) and the 88 harness and connectors. So this is my confusion, I have no idea where the wires go. Most of them just don't match up! Warning: Big pictures ahead.

    2013-09-05 14.39.26.jpg
    2013-09-05 14.39.54.jpg

    2013-09-05 14.40.21.jpg
    2013-09-05 14.40.53.jpg

    2013-09-05 14.41.26.jpg
    2013-09-05 14.41.39.jpg
  12. There was a major redesign in the wiring in 91 and later cars. It is different both with the wire colors for a circuit and some of the circuit functions like the turn signals and fuel pump.

    Multifunction turn signal switch:
    Before you think about replacing the multifunction switch with one from the junkyard, here's some things to be aware of...

    The problem is more common in GT models because they had fog lights on the same power wiring as the headlights. Ford undersized the wire and that caused problems.

    A word of caution about multifunction switches is in order here. The multifunction switch (high/low beam, wiper, turn signals) are different for different years. 87-98 will work in any 87-89 car. The 90-93 switches only work in 90-93 cars. You can't put an early model switch in a late model car, nor can you put a late model switch in an early car.

    Supposedly you can move the pins around to make the switches work in model years that are different from the car the switch came out of. I cannot verify that and haven’t tried it.

    Other possible problem sources for the turn signal & headlight malfunction are the ignition switch, multifunction switch and the plastic shell that holds the turn signal wiring connector pins.

    The following diagram is for 87-89 model cars.

    Turn signal switch wiring:
    MikeUrban likes this.
  13. So I got the turn signals working! I just cut both connectors off and soldered the harness to the new connector. Bam, turn signals work. Now its just wipers and high beams, which I'm still lost on seeing as though they don't share colors or number of wires. ugh
  14. My high beams still don't work, I can't find any wiring diagrams for them either. Anybody have an idea on how to trouble shoot this thing?
  15. PM me your email address and I will send you a complete Ford Factory 89 Mustang electrical diagram set. The zip file is 2.5 MB and is too big to fit through Stangnet's email gateway. The 88 and 89 are similar enough in the body electrical deparment that you should be able to use them without any problems.

    89 Mustang wiring diagrams zip package–

    They are in a zip file format to reduce the size of the package. If you don't have Windows 7 or Windows 8, you’ll need WinZip or other Windows archive tool to extract them from the zip file.. See www.majorgeeks.com - Download Freeware and Shareware Computer Utilities for a free download.
    The diagrams show the location area and the connectors are drawn to the same shape as those in the car.
    You will need the Adobe Acrobat viewer which is also a free download – www.adobe.com/products/acrobat/readstep2.html - Adobe Reader download - All versions
    stykthyn likes this.