791ttt

Attempting to fix the low fuel level indicator light, I removed the instrument cluster from my 1994 Toyota pickup and replaced the bulb, no go. When I replaced it, the tach didn't work. Removed the cluster again, checked continuity where I could, replaced it again. Now the neither the tach nor the speedo work and the fuel and temperature gauges go full scale.

Oil pressure gauge, voltmeter and the seat belt, brake battery and check engine warning lights seem to be OK.

I've also checked and tried to adjust the pin to printed circuit board connections.

Anyone have any trouble shooting ideas? Can't find a good wiring diagram.

Hadmatt54

Sounds like you lost the ground on your cluster (brown wire on a 4 Runner should be the same on the pickup). I think it is grounded under the drivers side kick panel, so are the radio and speakers...are they working properly?
I'd lift the ground, verify continuity back to the cluster, clean both connections, make sure it is making good contact with the cluster printed circuit and the body once reinstalled and see if that solves your problem.

791ttt

Thanks for the reply. Speakers, instrument lights, voltmeter and oil pressure gauge all working OK, although the radio has a bit more static than it used to.

Looked under the dash by the kick panel and found two brown wires and two white with black wires bolted to ground. Both pairs looked good. Pulled the instrument cluster again, only has two white with black wires to ground in different connectors, no brown wires.

Checked continuity of both w/b wires to ground and both were good. Disconnected wires at kick panel and still get continuity to ground????, so reconnected them. Plugged in a second panel my son had gotten and both the fuel gauge and temp gauge still went full scale.

I'm at a total loss. Has to be something common, but can't figure out what it is.

791ttt

While trouble shooting further, all connectors in place, AC wasn't working. Idle would go up, but the compressor clutch wouldn't engage. Disconnected all connectors from the instrument cluster and the compressor engaged. reconnected the blue, white and grey connectors, left to right, and compressor stayed engaged. Connected the last white connector and the compressor disengaged. There are 7 wires and 5 blanks in this connector. White/Black ground wire checks to ground OK.

Any thoughts????

791ttt

You were right. After searching further, found two broken wires. One for the tach feed and the other a common ground that was sort of brown. Everything working now, except for the low fuel light that I haven't found a wire for. Thanks.

Hadmatt54

Is your truck an SR5? Only the SR5 models of the first gen trucks had the low fuel light. If yours has it, generally Toyota uses a yellow/red wire for the low fuel light. The easiest way to test is unplug the gauge harness at the tank and jumper the wires as stated below. The test procedure is as follows:-
Fuel Level Warning System
1. INSPECT WARNING LIGHT
(a) Disconnect the connector form the sender gauge.
(b) Connect terminals 1 and 3 on the wire harness side
connector.
(c) Turn the ignition switch ON, check that the warning
light will come on.
If the warning light does not come on, test the bulb.

Orientation of the connector is as folows:- With the connector lock tab at 12 o'clock, #1 is top left, #2 is top right, #3 is bottom left, #4 is bottom right.
1&3 and 2&4 are not directly in line, but this will give you a general idea as to which wire is which. If this test lights up the bulb then your problem is the sending unit.

791ttt

Thanks again. It is not an SR5, that would explain it. I had checked the bulb and it was OK. When I pulled the cluster to repair the two broken wires, I searched through the bundle and couldn't find a yellow/red wire anywhere. Gave up and put it all back together.

Hadmatt54

The easiest check to verify if your truck came with that option is to check the gauge sending unit at the tank. if it has 3 wires then it is one with a low fuel light option. if it only has 2 wires then your truck does not have that option.

791ttt

I'll get under the truck and take a look. My son's '89 has a low fuel light but he says it is an SR5. Will try to let you now in a couple of days. Appreciate your help.

wiseguymmiv

OP, any pics you can post of this would be appreciated. My low fuel light no longer works. I have the SR5.