No Brake Lights, Turn Signals, Tach, Fuel Gauge

1929 Views 24 Replies 11 Participants Last post by awlb, 4 mo ago

gmuiter

Discussion Starter · May 21, 2022

Hello friends.

1994 NAS D90 Soft Top, 105k miles.

Everything working perfect until I take it to the garage for the PA state safety inspection! Literally drove to their lot, made sure brakes and signals etc worked and expected a fast and easy inspection since I only put 200 miles on in the last 12 months. But alas, not to be!

Whats not working:

Brake lights
Turn signals
Tach not functioning
Fuel gauge not functioning
Front Wipers and squirters not functioning
No reverse light

What is working:

Every other electric!
Headlights
Horn
Parking lights (fore and aft)
Starts and runs, drives fine.

Here is what I've done:
Got it to pass inspection when I wiggled the turn signal relay. Seemed to come right back on and everything worked. So, I replaced the relay with a new one from AB and everything continued to work for about 60 seconds. Now Im back to all the above being dead again. Again everything just was functioning as it should have and now, nothing.

I checked every single fuse in front of the gear shift in the interior. Pulled each one, visual inspection and all were good.
Checked for loose wires, corrosion at the tail lamps. I recently replaced the bulb carriers so Im 99% certain those are in good condition
Ran a continuity test from the bulb carriers and had audio confirmation the circuits were good (brakes applied, signal stalk on etc...)
Pulled steering wheel off, disassembled the column to check for loose wires - nothing (I had replaced a couple years ago the turn signal stock with new)
Double checked the newer relays in the passenger (RH) footwell as sometimes my kids kick up there unknowingly and knock something loose.

At a loss and appreciate specific guidance. I should admit I did search here for this issue and found many entries of the same/similar but their fixes did not resolve my issue.

Im certain many of you will say, "check your grounds" but if you can be specific as where exactly I should be looking that would be appreciated! Thank you in advance!!!

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ionfender

· #2 · May 21, 2022

Regarding the lights, have you checked or replaced the hazard switch?

My turn signals didn’t work, and it turned out to be a bad connection at the hazard switch.

Reactions: 1

gmuiter

Discussion Starter · #3 · May 21, 2022

ionfender said:
Regarding the lights, have you checked or replaced the hazard switch?

My turn signals didn’t work, and it turned out to be a bad connection at the hazard switch.

Oh yes - really important point I forgot to mention! There is NO hazard switch! Some PO must have removed it ? No idea about it other than the 8-10 years I have owned this, never an issue but again, no hazard switch anywhere to be found.

ionfender

· #4 · May 21, 2022 (Edited)

In that case sounds some (or all) of the wiring is custom/modified, and makes it difficult to trace via a web discussion.

Will need pictures, or more likely someone local to look at it.

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Defender901991

· #5 · May 21, 2022

Hows the battery? But sounds like a wiring issue with no hazard.

rdavisinva

· #6 · May 22, 2022

Green circuit has no power. Suggest you consult a wiring diagram and trace through the IG SW into the fuse box.

mffoster

· #7 · May 22, 2022

Does not have to be “custom wiring” to remove the hazard switch on a 94 NAS 90. Decades ago I put 3 gages in the center of my truck. Just unplugging the hazard switch meant that none of the lights/turn signals worked properly. If I recall I had to use a wire to jump a couple of connections on the hazard switch connector so everything worked correctly. Then taped and stuffed the connector into the dash behind the gages where it has been ever since. So… perhaps dig around in the dash behind the cover in the center and try to find the original connector. If it was done like that and the jumper came loose it might be an easy fix.

Sent from my iPad using Tapatalk

Rocky

· #8 · May 22, 2022

Is it tempting to clean up the PO mess, and install a working Hazard switch? Hazard Switch Wiring Harness (*includes* Carling Hazard Switch & Multiplug) - Switch Plates

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gmuiter

Discussion Starter · #9 · May 22, 2022

rdavisinva said:
Green circuit has no power. Suggest you consult a wiring diagram and trace through the IG SW into the fuse box.

You're onto something here! Thanks for this lead. Every part of the green wires traced is impacted so I will run this down from the fuse box and see if I can locate and will report back This helps narrow down what wire(s) to look for. Thank you!

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waveridin1959

· #10 · May 22, 2022

I had this issue and it was related to the rear brake lights shorting at the connecting from getting wet. It would slowly burn out the fuse without blowing it. The points on the brake lights would melt too. The fuse would slowly melt. I put dialectric grease on the brake light connectors to fix it.
My gauges would work until I hit the brakes and they would cut out.

gmuiter

Discussion Starter · #11 · May 22, 2022

waveridin1959 said:
I had this issue and it was related to the rear brake lights shorting at the connecting from getting wet. It would slowly burn out the fuse without blowing it. The points on the brake lights would melt too. The fuse would slowly melt. I put dialectric grease on the brake light connectors to fix it.
My gauges would work until I hit the brakes and they would cut out.

Well - I think I've sorted this thank you ALL!

So here is what I think happened. On the back of the fuse box where the green wire goes in to the 10a fuse, the metal, female receiver portion the the 10a fuse goes into had pushed out of the back perhaps just enough that the connection required was just simply not solid enough. I looked at that fuse many times and visually it appeared intact. I replaced that fuse, coated blades in dielectric grease and made certain the receiver stayed put.

This ended up to be what seems to be a nice simple fix. Im going to get it all back together and on the road today to test and will report back for future owners to reference for certain.

But for now, all systems seem to be a GO! Thank you again for all the help!

As always, this group of owners and enthusiasts are a tremendous help. Thank you!

Reactions: 1

rdavisinva

· #12 · May 22, 2022

I hope you feel accomplished for a job well done.
The simplest fixes are often based on a hint or clue.
Glad you are up and running.

gmuiter

Discussion Starter · #13 · May 23, 2022

Confirmed its a fix! Just drove it and all is right in the world! Thank you again!

Reactions: 4

benzaken

· #14 · May 26, 2022

Maybe you can come fix my Defender 90 next. My speedometer goes on/off, tach oscillates, whenever I turn up heat fan to high, or turn on windshield wipers.

gmuiter

Discussion Starter · #15 · 12 mo ago

Well team - Im back and the same issue but now seemingly worse. I had the same issue pop up where when I shut the engine off, I tried to re-start a few minutes later and nothing, nada. No turn over, no gauges, no brake lights, no wipers etc... I tried checking all the fuses again but this time, it did not resolve the issue.

So here is what I have done.

1) Checked that the batteries were good, both reading 12.34v
2) Replaced the ignition key barrel and the switch at the end (came new with it) - yay new keys finally!
2) Pulled the main fuses under the bonnet, checked and re-seated them with dielectric grease.

Some success! I now have the gauges back, wpiers and brakes. - HOWEVER -

When attempting a start, I smoked a small black wire which appears to be coming from the starter relay. The plastic shielding melted off that wire and up into the bundle.

So - where do I even start to look? I know I need to replace this wire but I cant seem to locate where that wire goes.

Check out the youtube video HERE showing the smoke show!

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Roverchef

· #16 · 12 mo ago

You are missing(corrosion) a ground somewhere. Check all chassis to motor, battery to t-box, etc. Worst case you could add a ground directly from the battery to the drivetrain and see if things start to wake up.

rdavisinva

· #17 · 12 mo ago

Diddo. Bad grounding from battery to chassis and or engine.

gmuiter

Discussion Starter · #18 · 11 mo ago

Guys - here was the issue. The starter relay failed to "close" I think. It sent all the voltage down the ground wire and burned it completely out; the entire length of the ground wire melted. After running a new ground wire from the female end of the relay and replacing the relay, it fires up and runs again. Hope this can help others if the situation presents to another member here. Thank you all.

Roverchef

· #19 · 11 mo ago

gmuiter said:
Guys - here was the issue. The starter relay failed to "close" I think. It sent all the voltage down the ground wire and burned it completely out; the entire length of the ground wire melted. After running a new ground wire from the female end of the relay and replacing the relay, it fires up and runs again. Hope this can help others if the situation presents to another member here. Thank you all.

Still sounds like you are missing a "primary"ground somewhere. For that to melt down someone held the starter tooooo long and it back fed the ground.

gmuiter

Discussion Starter · #20 · 11 mo ago (Edited)

Roverchef said:
Still sounds like you are missing a "primary"ground somewhere. For that to melt down someone held the starter tooooo long and it back fed the ground.

I added a new heavy duty ground from the engine block, passenger side to the inside of the wing. I did confirm all the other grounds were solid. Even after this, the wire continued to smoke upon attempting a start. I traded out relays but at that point it was too late as that ground had smoked through the plastic.

But I do agree, why would that have happened in the first place? Bad main ground somewhere, or open relay redirecting current when it shouldn't have?

And, to note, the instant I turned the key to start the truck, the smoke appeared. Check out the you tube video I had posted above. (HERE )

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