Hey guys,

I have a newb question...I have a 1987 4runner turbo with a digital dash. When I turn the headlights on the dash sometimes flickers. When the headlights are on and I turn on the heater, fog lights, open window the dash flickers and then only some of the dash lights light up. Then the wierd thing is the temp guage will start to go into the hot zone. If i tap the power window switch the dash blanks out and everything returns to normal. I cant figure this out and I have had two mechanics look at this and they cant find anything. Any help would be appreciated.
Thank you...

 

check yer grounds.

 

I tried to check them all but I know I am probably missing them. Where can I get an electircal schematic to check them?
Thanks..

 

check the main topic list of this forum
look for the 'pinned' posts referencing the FSM

 

Thank you for the input.

 

Main cab ground point is behind the drive's side kick panel, a large screw into the sheet metal with a mess of brown ground wires connected to it. Don't just look at it and say it is OK, actually remove the screw, wire brush the terminal rings and sand the sheet metal under the screw and then put all the wires back. I like to use some dielectric grease or metal base anti-sieze compound on the terminals to prevent oxidation. I had a problem related to that screw with my cruise control shutting off at random times. Cleaned all the grounds there (one was for the c/c) and that fixed that problem.

 

I had the same thing happen to the digital dash on my 86' 4Runner. I have also heard of this happening a bunch on other sites, posts etc.

I was having close to the same problem with my 86 Turbo SR5 4Runner, sometimes it would work and sometimes it would not. It would also go crazy and everything would flash different numbers, different miles per hour and the scale would change. It seemed to get worse when I turned on any other electrical item (the dash would turn on and off when I would turn the turn signals on). Later on the starter started having problems and I realized that there must be some kind of electrical problem. I tore apart the dash and checked all the powers and grounds, everything tested good. I ended up tracing the problem to the negative battery terminal cables, it was not grounded well enough. I added larger 4 gauge wire and made an extra ground that goes to the firewall. After fixing the problem I have not had the dash act up, it starts first try, the dash lights are brighter than ever, and everything overall seems to work better.

I know that's not the exact problem your having, but it seems pretty close.

 

Thanks guys...I will tackle that next weekend. If that doesn't work...any other suggestions?

 

find a Catholic priest and have your demons exocised?

honestly though, check out what has been suggested, and come back here and explain (honestly) everything you've done to track down the problem(s).

 

ok guys...here is what I have done.

First off..thanks for the advise.

Just a little history.

Well...my battery as of late has been discharging and had no juice.

I just had a new alarm put in because my mechanic said that what was drainning the battery.

I thought they must have left a ground loose that should be fairly resonable to fix....YEAH RIGHT!

I finally got a day off work that I could spend under the hood and under the dash. I first started under the hood and worked on the the fender panel next to the battery. I removed all grounds that I could find and sanded the sheet metal and wire brushed the connectors.

I then went to the other side and did the same for all the other grounds I could find. I did notice that when the shop put my alarm in they grounded one wire but also attatched a plastic relay on that same ground. I removed the plastic relay and just left the the ground grounded by itself.

I then went under the hood and did the same thing with all the ground that I could find. One note...there was a ground that attatched to the dash with a screw going through to sheet metal. Basically....the grounding wire over plastic and attatched to sheetmetal with a screw.

Well...I jumped the truck and it started right up...no white smoke and heated up pretty quick (odd). The truck drove great and the lights seem to be brighter. But the dash was still flickering...I would say more than normal.

I figured that I would park it and check again. When I parked it...and tried to start it again, it will not start. The volt meter says I have juice but it will not start.

I am not sure what I did or what to do next.

Anyone have anymore advice???

 

Have you taken the battery terminals off and cleaned them real well? Make sure your battery cables aren't full of corrosion too. Sounds like a sneaky battery connection to me. They can be a real PITA to diagnose sometimes

 

an alarm is never going to drain your battery unless you leave it armed from about 3 years straight. This is the mechanics way of saying he has no idea what the real problem is and i want this car out of here. "Alarms fault"

An alarm will draw about the same current as the clock memory in your radio.

You have other issues as far as a draw goes. If you cant figure it out, take it a real electrical shop. Not a general mechanic.

Not start nothing, or cranks and doesnt start.

 

dont run away from the fact that ur neutral safety switch could be going out and thats whats not allowing u to start... they love to pick and choose when to work on these old gems!

 

By no start, you meant no crank, no fuel, or no ignition?

+1, and good that you did this.
Toyota's rely on contact from sheet metal thread, to coated (possibly oxidized) bolts to ring terminal for ground. Sanding to bare sheet metal and putting conductive grease on contacting surfaces , gives you more direct and corrosion-resistant connection.

+1. Yes, you need an electrical expert.


+1, Inspect and clean terminals thoroughly I learned my lesson, too

If truck has auto transmission, it will have neutral safety switch, If manual, clutch position/safety switch.