I'm having some problems with my 1985 SJ410. I owned this car for about 2 years, and drove maybe 4000km with it.

The biggest problems are:

1. Voltage gauge in dash seems low. See the amazing illustration I have attached. This could mean nothing though (defectiv gauge) - I have never seen it in the middle part of the yellow before.
The battery seems fine - It meassures 12.6V - even after staying parked in the garage for 3 months. When driving I meassured it to 13.6 - that is a bit low?

2. Brake lights doesn't work. All other lights works. But the weird thing, sometimes they will just start working again. Luckily, for no reason, they started working the day of last state inspection
Checked the sensor at pedal, and it moves fine.

3. Ignition will sometimes not light up dash when I turn the key to ON (not starting). Usually the dash light should come on immediately. But sometimes they will not light up for some time. They always come on at one point though, not sure if it's because I try to switch key on/off, or it's just a matter of waiting. Important to note though: When I turn key to ON and no lights show in dash - stereo will still play, and the starter engine will turn if I try - but engine will not start

Other things not working:
- 4WD light (worked when I first bought the car)
- Air fan - It worked one time, but after that never.


What I already tried:
I checked all ground wires I could find in the engine compartment. Also did a complete reinstall of battery terminals w/wires.

I looked at the grounds under the rear lights. I unscrewed some and cleaned, but some had stuck screw so I couldn't - but it all looks good...

What are some other ground points I should check? I can't really find any ground wires near the fuse boxes? I think there was one tiny wire infront of the door, is that all?

Are you getting 12v to the brake lights when you hit the brakes?  It might be the brake light switch itself that is causing an issue.  Did you check resistance across it when it activates?

13.6v should be fine.

4wd light I believe is ground controlled, from the switch on your transfer case.  Would need to track down the wiring diagram.  Usually it's a switch issue, you can unplug the transfer-case and bypass it and see if it works.

The dash lights sounds like a ground issue.  Again, make sure you are getting 12v up to the dash.