Electrical Questions

wyoung74

New Member
Jul 16, 2019
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Hello all,

Reposting this from the welcome wagon in the hopes of catching more eyes...

I just bought a 91 hatch roller that's set up for an LS swap. I think I'm going to continue down that path. The body is straight, great interior, decent paint, straight subframes, torque boxes, and strut towers. I'm excited to work on this, and I'm sure I'll be needing assistance from this site.

I'm just digging into this and the engine bay is bare right now. I have a pile of wiring harnesses to sort out and I've found a lot of helpful diagrams so far. I am NOT a wiring expert, and one question I can't seem to answer is... the harness coming through the firewall on the driver's side.. is there a diagram/picture that shows what each connector is? There's nice pictures for the engine harness and ecu harness, but I can't find one for the dash harness where it comes into the engine bay. I'm currently trying to determine what electronics work, so my plan is to identify how to run power from the battery into the car without the engine (through the starter relay) and see if the lights, blower, windows, etc all still work. Do I just hook battery to ground and hot side to the starter relay and then hook the yellow wire with all the fusible links on that side to the starter relay post not already used by the battery? Will that allow me to assess the electronics safely without having to worry about burning anything up? Any help is greatly appreciated. I've done body work and I love working on engines, but I've never jumped into auto electrical work besides adding minor ugrades like fog lights, etc, so this is a new challenge. I've already ordered a Bishko CD which should be here in 2 weeks, but I'm trying to see what I can learn in the mean time. Thanks All!
 
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jrichker

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Look for a 91 Mustang EVTM (Electrical & Vacuum Troubleshooting Manual) - use Google and you may find one that you can download. It has pictures of the wiring and component locations.
 

TOOLOW91

If you're the village idiot what's that make me?
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Nov 29, 1999
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Hello all,

Reposting this from the welcome wagon in the hopes of catching more eyes...

I just bought a 91 hatch roller that's set up for an LS swap. I think I'm going to continue down that path. The body is straight, great interior, decent paint, straight subframes, torque boxes, and strut towers. I'm excited to work on this, and I'm sure I'll be needing assistance from this site.

I'm just digging into this and the engine bay is bare right now. I have a pile of wiring harnesses to sort out and I've found a lot of helpful diagrams so far. I am NOT a wiring expert, and one question I can't seem to answer is... the harness coming through the firewall on the driver's side.. is there a diagram/picture that shows what each connector is? There's nice pictures for the engine harness and ecu harness, but I can't find one for the dash harness where it comes into the engine bay. I'm currently trying to determine what electronics work, so my plan is to identify how to run power from the battery into the car without the engine (through the starter relay) and see if the lights, blower, windows, etc all still work. Do I just hook battery to ground and hot side to the starter relay and then hook the yellow wire with all the fusible links on that side to the starter relay post not already used by the battery? Will that allow me to assess the electronics safely without having to worry about burning anything up? Any help is greatly appreciated. I've done body work and I love working on engines, but I've never jumped into auto electrical work besides adding minor ugrades like fog lights, etc, so this is a new challenge. I've already ordered a Bishko CD which should be here in 2 weeks, but I'm trying to see what I can learn in the mean time. Thanks All!

Make sure your starter cable isn’t hanging where it will short to ground same goes for your alternator .

You can power the constant side of the starter relay up with all the fusible links and yellow wire on it and test everything in the car .
 

wyoung74

New Member
Jul 16, 2019
3
0
1
31
Pennsylvania
what else from that driver's side harness is needed? I'm having a tough time finding an image of what all comes out through that grommet..