Electrical 1986 (5-spd) mustang reverse lights not working.

Driver460sz · May 11, 2019

Bulbs are good, all others work, fuse is good. Checked the wiring/plugs on the trans and they are connected and seem fine. The car does have wires tapped and "updated" under the dash and around the fuse panel. God knows what that is at this juncture and if it has anything to do with the reverse lights (Waiting to hear from the previous owner). At the back of the car, there is a little device (a box thing) that has a ground (Black) and a red leading out (What is this device?). The red wire was cut, which I re-attached to see if that did anything. Made no difference.

Anywho.....Outside of trying a new trans harness sensor.....whats the next step in the diagnostic process? Any hidden switches maybe???

Thanks y'all

JosTee · May 11, 2019

Normally there is a switch on the transmission. So when you select reverse this switch is activated. Can you find the wiring and maybe check if there is voltage on one of the wires. Can you short the pins when there is voltage on it, rearlight should go on then.Otherwise remove the switch from the housing and see /measure if it is working if you have a multimeter.

Mustang5L5 · May 11, 2019

If you jump the plug out at the switch on the trans, do they come on?

Driver460sz · May 11, 2019

The car want from auto to standard with the last owner. I think they skipped something.

Mustang5L5 · May 11, 2019

Only thing you need to do in an auto to 5-sos swap is unhook the harness from the AOD, hook up the small 1 foot long t5 harness and plug it into the reverse light plug on the side of the t5.

If you unplug it from the t5 and jump the 2-wire plug out, the lights come on

fredfifty · May 13, 2019

had the same problem, switched out the sensor that threads into the trans and all was good.

General karthief · May 13, 2019

not getting picky here but terminology here can be important, in this case it would be a 'reverse light switch'.
sensors
senders
switches
then maybe I'm just getting old and not kept up with the changes

Driver460sz · May 13, 2019

Well............this is getting fun! What I know is that the speedo doesn't work, the car starts without depressing the clutch, and the reverse lights do not work. I do know that the circuit closes when put in reverse as checked by jumping a wire from the battery to the posts on the trans and using a meter. It doesn't seem anything is coming through from the harness in the car to the trans tunnel.

Maybe need a speedo gear for speedometer, check to see if a neutral safety switch got bypassed. From what I understand the NSS and the reverse lights interlink and this could be the problem. Somewhere near the master cylinder is the location, I believe.

Mustang5L5 · May 14, 2019

Reach up under the dash by the clutch switch, find the two small loose plugs. One gray, one clear. Remove the jumper in one and install both into the clutch switch.

As far as as the reverse lights, all you do in a swap is unplug the harness from the AOD and plug this into the harness and connect to reverse light switch

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Use this direct replacement 5.0 Resto reverse light harness to fix a ripped, torn, or malfunctioning harness!

lmr.com

Red loop jumps the nSS

If you don't have power on the wires, pull the drivers kick panel, locate the 8-wire trans harness plug (aod will have 6-wires due to no wires for the ngs on top of the trans) and test for power on the reverse wiring.

I'll see if I can get wiring colors for you. What year is the car

Driver460sz · May 14, 2019

Mustang5L5 said:
Reach up under the dash by the clutch switch, find the two small loose plugs. One gray, one clear. Remove the jumper in one and install both into the clutch switch.

As far as as the reverse lights, all you do in a swap is unplug the harness from the AOD and plug this into the harness and connect to reverse light switch

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Use this direct replacement 5.0 Resto reverse light harness to fix a ripped, torn, or malfunctioning harness!

lmr.com

Red loop jumps the nSS

If you don't have power on the wires, pull the drivers kick panel, locate the 8-wire trans harness plug (aod will have 6-wires due to no wires for the ngs on top of the trans) and test for power on the reverse wiring.

I'll see if I can get wiring colors for you. What year is the ca

Mustang5L5 said:

Reach up under the dash by the clutch switch, find the two small loose plugs. One gray, one clear. Remove the jumper in one and install both into the clutch switch.

As far as as the reverse lights, all you do in a swap is unplug the harness from the AOD and plug this into the harness and connect to reverse light switch

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Use this direct replacement 5.0 Resto reverse light harness to fix a ripped, torn, or malfunctioning harness!

lmr.com

Red loop jumps the nSS

If you don't have power on the wires, pull the drivers kick panel, locate the 8-wire trans harness plug (aod will have 6-wires due to no wires for the ngs on top of the trans) and test for power on the reverse wiring.

I'll see if I can get wiring colors for you. What year is the car

Click to expand...

Awesome and thanks. It is a 1986.

Driver460sz · Jun 10, 2019

Mustang5L5 said:
Reach up under the dash by the clutch switch, find the two small loose plugs. One gray, one clear. Remove the jumper in one and install both into the clutch switch.

As far as as the reverse lights, all you do in a swap is unplug the harness from the AOD and plug this into the harness and connect to reverse light switch

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Use this direct replacement 5.0 Resto reverse light harness to fix a ripped, torn, or malfunctioning harness!

lmr.com

Red loop jumps the nSS

If you don't have power on the wires, pull the drivers kick panel, locate the 8-wire trans harness plug (aod will have 6-wires due to no wires for the ngs on top of the trans) and test for power on the reverse wiring.

I'll see if I can get wiring colors for you. What year is the car

86

Electrical 1986 (5-spd) mustang reverse lights not working.

Driver460sz

JosTee

Member

Mustang5L5

That is…until I whipped out my Bissell

Driver460sz

Mustang5L5

That is…until I whipped out my Bissell

fredfifty

General karthief

wonder how much it would cost to ship you a pair

Driver460sz

Mustang5L5

That is…until I whipped out my Bissell

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Driver460sz

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

Driver460sz

Mustang Manual Transmission Reverse Light Harness (87-93) FH-055

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Electrical 1986 (5-spd) mustang reverse lights not working.

Member

That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

wonder how much it would cost to ship you a pair

That is…until I whipped out my Bissell

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