1993 FZJ80 - Still can't get the P & D lights to work on the dash. (1 Viewer)

Joined
Dec 27, 2018
Messages
410
Location
Auburn Alabama
Hello all, I have been trying everything I can find online to figure out why these lights don't work on the dash. The truck runs great and shows no apparent issues. Occasionally the reverse light won't illuminate unless the shifter is in the perfect position. I replaced all the bulbs in the dash with the correct led bulbs and for the shift indicators I have: R (Occasionally), N, L, 2nd, Pwr, OD. I have attempted the bulb in multiple different orientations - the previous bulbs were not blown. I made sure the harness clip was seated properly multiple times and tried known working bulbs. I need some direction to go here. I searched but most threads are just stating the D being out is an "80 Series Right of Passage". How do I troubleshoot this to determine whether its sensor related, wiring related, or something else entirely?
 
Joined
Feb 26, 2018
Messages
442
Location
Utah
Two places to check in my experience.

The main engine wiring harness passes over the engine on the firewall in the engine bay and then comes forward and past the EGR tube before going past the head downward. There are clips that fail and the wiring rests and burns against the EGR.

The other spot is the Neutral Safety Switch wiring. Sometimes the split loom fails on top of the tranny (95-97) but on the 93-94 you can have leaky Pesky Heater Hose coolant dripping on the harness connectors by the starter that cause corrosion in the connections.
 

voodu3

SILVER Star
Joined
Oct 13, 2017
Messages
994
Location
Signal Mountain,TN
X2 what @clayinho said. I would definitely check the plugs on the NSS wiring. You can also adjust the position of the NSS on the side of the transmission. When I installed a new NSS I had to loosen the mounting bolts and position it so the lights on the dash corresponded with the shifter. The holes are oval to allow for the adjustment.
 
Joined
Dec 27, 2018
Messages
410
Location
Auburn Alabama
Two places to check in my experience.

The main engine wiring harness passes over the engine on the firewall in the engine bay and then comes forward and past the EGR tube before going past the head downward. There are clips that fail and the wiring rests and burns against the EGR.

The other spot is the Neutral Safety Switch wiring. Sometimes the split loom fails on top of the tranny (95-97) but on the 93-94 you can have leaky Pesky Heater Hose coolant dripping on the harness connectors by the starter that cause corrosion in the connections.
I gave the harness a once over today and everything looks ok - I'll get in there better tomorrow and make sure the clips are in good shape - the heat reflective material has worn off on the harness I may wrap it in some material to protect the wires better.

I had a pretty gnarly coolant leak before overhauling the system so its likely coolant might have messed up the plug a bit. If the harness is in good condition I may pull the NSS.
X2 what @clayinho said. I would definitely check the plugs on the NSS wiring. You can also adjust the position of the NSS on the side of the transmission. When I installed a new NSS I had to loosen the mounting bolts and position it so the lights on the dash corresponded with the shifter. The holes are oval to allow for the adjustment.
How do you advise adjusting the NSS to position it in the right place? Just micro adjustments till all the lights work?
Yup...NSS component bolted to the side of the tranny. That will fail partially, not sending the correct signal to the correct 'bubs'.
10-4.. Hopefully it hasn't failed partially. I know a lot of people have had luck taking it apart and cleaning up the insides.
 
Last edited:

voodu3

SILVER Star
Joined
Oct 13, 2017
Messages
994
Location
Signal Mountain,TN
I had a pretty gnarly coolant leak before overhauling the system so its likely coolant might have messed up the plug a bit. If the harness is in good condition I may pull the NSS.

How do you advise adjusting the NSS to position it in the right place? Just micro adjustments till all the lights work?

Check the plug first. If you had coolant leaks I bet that’s your issue. For adjusting the NSS I loosened the bolts and rotated it all the way to the back of the slot. The lights were barely on or not at all on this position. I rotated it forward and had my daughter move the shifter until they all lit up. Then I tightened it down.
 
Joined
Feb 26, 2018
Messages
442
Location
Utah
I had my wife come out and watch the dash as I wiggled the harness. She verified that the gear light would flicker when I jostled the wiring. I couldn't have made the observation without a helper.
 

NorCalFJ100

SILVER Star
Joined
Feb 13, 2016
Messages
1,183
Location
Los Angeles, CA
I concur with NSS...my truck had a shoddy wiring repair...which I fixed, but still didn't fix my issue. Which was the same as yours. Eventually I had an issue with my NSS and needed to pull it. Low and behold, one of the male connections on the switch was broken. Would have never seen it without pulling it. So maybe do the same just to be safe.
 

voodu3

SILVER Star
Joined
Oct 13, 2017
Messages
994
Location
Signal Mountain,TN
This is what I found when I started to fix mine. I got a used NSS and the engine side plug from @slow95z and she’s good as new.

18340FAD-6866-49EF-9A53-0013CE9027E8.jpeg
 
Joined
Dec 27, 2018
Messages
410
Location
Auburn Alabama
I had a minute to start playing with things and started at the nss plug in the driver side footwell (photos below). I cleaned them up using a pick and electrical contact cleaner and proceeded to apply dielectric grease. Still no P/R/D lights - went to nss to adjust using the 12mm bolts with my room mate in the driver seat and I couldn’t get any of the faulty lights (P/R/D) to work. Is there a way to test at the harness to see if all 8 pins are getting power? They are all there and intact. Where do I go from here?

1AA26645-C1E5-4DD4-A7C5-49CB784F1594.jpeg
FED30F8A-E478-4A0F-90D7-C484508B3F91.jpeg
A50DB34E-4DFF-435F-8CED-CF3C876D98A7.jpeg
0B89C8F1-FADC-4209-A443-E149493D7072.jpeg
D4AE9223-6627-4DD1-9511-819F1E47907E.jpeg
 
Joined
Feb 26, 2018
Messages
442
Location
Utah
At least on the 95-97, with that plug taken apart, you can test the pins from there (the engine side of that connector) to where they plug in to the ECU. I'm not sure where they go on the 93-94, but a quick glance at the EWD would show that. Basicallyyou would be testing continuity.

Those pins look pretty corroded and I'm not certain that they aren't your issue. You could remove the pins from the harness and give them a better cleaning?
 
Joined
Dec 27, 2018
Messages
410
Location
Auburn Alabama
At least on the 95-97, with that plug taken apart, you can test the pins from there (the engine side of that connector) to where they plug in to the ECU. I'm not sure where they go on the 93-94, but a quick glance at the EWD would show that. Basicallyyou would be testing continuity.

Those pins look pretty corroded and I'm not certain that they aren't your issue. You could remove the pins from the harness and give them a better cleaning?
I guess I should clarify all of those pictures were before the cleaning lol. Is there a better way to scrap off the corrosion then the pick? I’ll test next time I get a chance for continuity.
 

Users who are viewing this thread

Top Bottom