Did you simulate the sender resistance at various temps with the pot to check if the gauge functions normally?

A solvent (whatever you have handy) may remove a coating, or sand paper.

 

Yes, I installed the sender in its pocket, started the engine and checked the resistance while it idles , it starts with 650-700 ohms, then as the engine warms up drops to about 95 ohms, so it seems like sender is working fine. I also checked grounding the engine block to different ground points , same results meaning there is not grounding problem.

I then checked the resistance at the connector which hooks into gauge at the cluster panel. I do not get resistance between pin 1 and 2 from left. I checked no.2(brown) to ground, it's not ground. Is it supposed to be ground? I don't know where this brown wire is connected to ground, I could check.

In the picture I posted above 8th wire from left (red) is ground. When I check resistance between Pin1 and 8, I get the same resistance as sender resistance.

I'm not sure if brown wire should be ground and it is not and therefore the gauge is not working. I want to be sure before I connect that to ground and test.

I think we are getting close : ) -

 

Since you now have two console, if possible look on temp gauge circuit board for what electrical pins run to the circuit.

On wiring circuit.

Pin 1 is yel/grn (temp gauge), pin 2 is brown, pin 3 is yel/grn (light bulb sensor unit), 4 red (integration relay), 5 light green (ABS), 6 yel (trans gear bulb light), 7 blk/red (ditto), 8 red/blk (ditto), 9 grn/wht (ditto), 10 red (ditto), 11 orange or blue/wht (ditto) 12 grn/org (O/D switch), 13 blk/red (ign fuse).

 

Pin 1 goes to A,(top screw, towards the 13 pin connector) Pin 2(middle screw) goes to B and Pin 3(bottom screw, towards row of bulbs at the bottom) goes to one side of the first light bulb, the other side of the same light bulb comes from C, the same run feeds one side of the bunch of light bulbs.

I don't know if the above tells me if Pin 2 should be ground or not? Also it seems the gauge wiring is shorting somewhere otherwise it wouldn't read High. Correct? I'm not sure if it would do the same if it wasn't getting ground reference.

Pin 8 which was reading ground actually goes to it seems like one side of the Parking light.

 

Toyomoho,

Do you know which is the reference/ground wire for the temperature gauge on the back of a instrument panel?

If it is brown wire then it is not grounded.

According to what you wrote, no.8 wire from the left shouldn't be grounded and it is for the gear lights. Gear lights are working fine.

Pin 1 is yel/grn (temp gauge), pin 2 is brown, pin 3 is yel/grn (light bulb sensor unit), 4 red (integration relay), 5 light green (ABS), 6 yel (trans gear bulb light), 7 blk/red (ditto), 8 red/blk (ditto), 9 grn/wht (ditto), 10 red (ditto), 11 orange or blue/wht (ditto) 12 grn/org (O/D switch), 13 blk/red (ign fuse).

Like I said, I see the same resistance between Pin 1 and 8 as I get at the sensor and ground.

 

Could be wrong on wiring as don't have specific for this year.

But, gauge only has two external wires. Yel/grn for sensor and brown for ground. The 3rd connection is for DC power is which is on the board. The board circuit has gauge ground routed to the brown wire. No internal ground.

Would assume if both boards act the same, then can't both be bad and thus wiring.

If No 2 brown is not grounded, find out why.

 

8th wire from the left(red) on the above posted connector picture is ground, can I jumper red and brown to make brown a ground? This brown wire from IP goes to connectors under glove compartment but then I don't know where it goes, where it is grounded, if at all it should be grounded. I'm afraid to short this brown to ground if it is not supposed to be ground and hence asked for the confirmation from someone who knows.

 

Diagram states ground point is on top of engine. area between exhaust manifold and the two coils nearest the passengers side.

 

Are you confirming that Brown wire (the wire next to yellow/ green) is ground?

I haven't heard firm Yes or NO on this. If it should be ground, it will be really easy to jumper this out with another ground and check if that fixes the problem.

At the moment I get continuity to ground with 8th wire.(red/black)

 

The wiring diagram shows brown is ground. The gauge has two external wires, ground and the sender. DC power is supplied via the board circuitry that also powers other items.

Find the 3 circuit board connections for the temp gauge. One should go to yel/grn wire, one to brown and the other off to other board connections.

I don't know why red/blk is grounded. The gauge cluster has 20+ external wires. Your concern is only those for the temp gauge.