Back-up Lights

[90 Pony GT]

Backup lights aren't working, surprise surprise. Automatic transmission with inspection running up in 3 days. Replaced the back-up light switch, still nothing. Checked the voltage on the back up lights and got 0. Obviously something wrong. I figure the ground is good, because my brake lights work fine (guessing back-up and brake use the same ground). Fuse was checked and good. Only thing i can think of is the actual wire, but just wanted a little feedback before i rip up my carpet chasing wires. I should probably check the voltage on the back-up light switch, i'll edit this when i wake up tomorrow morning.
Any help is appreciated.

 

[90 Pony GT]

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[billison]

Did you check the plug on
The side of the trans?

 

[90 Pony GT]

Yea just checked it and it was good.

 

[mikestang63]

have you checked the wires for continuity. DId you put the car in reverse and check the sockets and wiring?

 

[90 Pony GT]

Sockets were checked and had no voltage getting to them. I think it has to do with my fuse box, the previous owner moved the fuse box and there's a ton of wires at the kick panel that are cut.

 

[mikestang63]

Sockets were checked and had no voltage getting to them. I think it has to do with my fuse box, revious owner moved the fuse box and there's a ton of wires at the kick panel that are cut.

ouch . sucks. @jrichker for schematic

Time to break out the DVM, test light, wire, soldering iron, shrink wrap and dive in.

 

[billison]

You can probably run a switched power wire to get you through inspection. But I'd get that stuff sorted.

 

[jrichker]

I don't have wiring diagrams for 90, but I do have them for an 89, which should help.

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.

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 MajorGeeks.Com - MajorGeeks - 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 – Adobe Acrobat Reader DC Install for all versions - Adobe Reader download - All versions

 

[90 Pony GT]

The more I look at this wiring diagram the more my head spins..... Gonna go throughout the car from the back toward the front.

I'll start from the reverse lights. 140 ( Black/Pink ) is the wire that powers them. ( Grid 98-89)

Runs throughout the car. (Grid 88-78)

Goes to this plug, which i'll get back to in a minute [Plug 140] (On the grid this is 75-D)

Back-up switch. Which has 140, but also brings in 298 (What brought in the confusion), which connects to the fuse box. (Grid 55-45)

Continuation of Grid 55-45

Couple of pics of Grid 44-34. Confusing as hell..... Mostly confused from where all these 298 came from and where they are going.

Last but not least, the last i could find of 140 and 298. I believe that the yellow highlighter section is the [Plug 140] which leads to the reverse light switch.
Purple runs to the other purple switch on the above picture? I see where the 298 wires come from that lead to the instrument cluster. My turn signals work, which is the lime line, so i know that works.
So i singled it down to the navy blue line, which comes from the purple line, and I'd like to think that's where its cut/not working. (Grid 33-23)

Any thoughts? Am I missing something here? Sorry for the long post, and the horrible color coding.

 

[jrichker]

The more I look at this wiring diagram the more my head spins..... Gonna go throughout the car from the back toward the front.

I'll start from the reverse lights. 140 ( Black/Pink ) is the wire that powers them. ( Grid 98-89)

Runs throughout the car. (Grid 88-78)

Goes to this plug, which i'll get back to in a minute [Plug 140] (On the grid this is 75-D)

Back-up switch. Which has 140, but also brings in 298 (What brought in the confusion), which connects to the fuse box. (Grid 55-45)

Continuation of Grid 55-45

Couple of pics of Grid 44-34. Confusing as hell..... Mostly confused from where all these 298 came from and where they are going.

Last but not least, the last i could find of 140 and 298. I believe that the yellow highlighter section is the [Plug 140] which leads to the reverse light switch.
Purple runs to the other purple switch on the above picture? I see where the 298 wires come from that lead to the instrument cluster. My turn signals work, which is the lime line, so i know that works.
So i singled it down to the navy blue line, which comes from the purple line, and I'd like to think that's where its cut/not working. (Grid 33-23)

Any thoughts? Am I missing something here? Sorry for the long post, and the horrible color coding.

None of the pictures are visible... There is something wrong, because I tried the manual no assist method and they didn't show up for me either. The problem could with be your web host for pictures.