Charles4x4

hi, my '87s digital dash flashes when I have the lights on and I first take off in 1st and 2nd gear. Maybe it's a loose connection somewhere, something with amperage, vibrations, or something else. Any ideas?

i'll try to post a video I took tonight.

Charles4x4

Video attempt:

Charles4x4

My fuel gauge flashes - if anyone has any ideas there as well. The PO put in an aftermarket one below the dash, but I'd love to get the original to work. I've heard it might be the fuel pump at the tank where a hair thin piece typically breaks or something else.

Co_94_PU

iTrader: (-1)

Stick em up, you are being thread jacked!

Hey is that cruise control light lit up when you go key on, is it just the camera lighting it up?


Back on topic. My digital dash does this also, or similar i didnt view the video no MOV player on my phone. I've only dug into it once and only a little, enough to know it simply a loose connection on the flexible circuit on the back of the gauge. I can do a partial power off, enough to cycle the integration relay behind the seat, to reset it.

Charles4x4

Well, the green seems to come on each time I open the door. I'll look at it to confirm, but I think it could be linked to the overhead lights. The PO disabled cruise control when he swapped to a manual tranny, so who knows.

How easy is is it to pull the digital dash or reach the flexible circuit on the back?

and where is the integration relay behind the seat that you can use? I just turn the engine off and it comes back on - but that is obviously a pain when trying to get somewhere.

ewong

here's a guess

Toyota trucks (of this era, as far as I know) are wired GROUND SWITCHED

this means

+12v >> device >> switch >> ground (neg battery terminal)

Most cars (and other devices) are wired POSITIVE Switched

+12v >> switch >> device >> ground (neg battery terminal)

This seems like a minor detail.

But it means that when wiring after things into the circuit - there is voltage where people do not expect voltage

Thus leading to all kinds of wiring gremlins.

Sorry for the bad news

This means finding ALL the "added wiring" and trying to isolate / re wire it....

Charles4x4

Thanks. Guess I'll start with the device and work my way backward. Hope to pull the dash this afternoon.

Charles4x4

Here's as far as I've made it. Time to get out the FSM.

Wonder why this one wire is cut - maybe the fuel gauge...looks like it is crimped then goes back down toward where the aftermarket fuel gauge is.

Anyone see anything loose that may be vibrating to cause the flashing?

Charles4x4

I found broken tabs at the bottom of the dash so I fabricated a few new ones out of some rubber I had laying around. I thought it could have been vibrating and causing the flashing. Worked fine tonight for 10 mins, then flashed again.

I messed with the blinker/light column and got it to reset by turning lights to driving lights or by using the blinker. Odd...

Charles4x4

The only other potential clue I could find was this black wire that is spliced into the black wire on the steering column behind the blinker. I followed it through the firewall on the drivers side. It then goes to the passenger side and is spliced into a bunch of wires as shown in the pics below.

Any idea what this is for? And maybe it's getting hot (since it only happens after driving for 5-mins or more with the lights in) and has a poor connection causing the dash to flash? I'm not sure how solid the connection is inside the electrical tape...

Charles4x4

And I gave up on the fuel gauge. I hooked the old wire up again but no luck. Since the aftermarket one works fine, unless there is an easy fix like a fuse somewhere I'll just let that one go for now.