MA61 - How do I troubleshoot temp gauge wiring - Solved

[Gibbon]

The temp gauge in my Digital Dash stopped working a few weeks ago. The gauge still lights up, but never moves from the bottom position - it used to sit in the middle and never move.

I've tried the "remove the connector from the sender and earthing" it to see if the indicator jumps to the top position - no change.

I've swapped over the entire dash cluster - no go - the indicator just sits at the bottom position.

According to the Toyota troubleshooting steps, it must be caused by a short circuit. How do I go about tracking this down

I've checked all the fuses and none are blown.

I've put a multimeter on the sender, and it's outputting something, so I'm assuming it's not a dead sensor.

Any help or pointers in the right direction would be great.

Thanks

[thechuckster]

trace the temp sensor wire from the egine bay/sensor to the gauge?

The sensor wont 'output' anything - it just changes resistance between the pin and ground as it heats up.

did you ground the right sensor connector? there are three on the thermostat housing: ECU temp, Cold Start Timer & Guage temp.

Cold Start is the largest of the sensors so it should be easy to identify (plus if you ground it, you'll blow a fuse).

[wilbo666]

He has a 1jzgte thechuckster (so no cold temp, ecu temp tho...).

I'd remove the dash and using a multimeter check the resistance between the temp wire on the dash and the temp wire on the engine (unplug from dash and unplug from engine temp sensor).

The resistance should be quite low, however it might be open circuit?

I'd also check the resistance from the dash or temp sensor wire to ground, if it is very low then it would indicate that you have a short!

Once you have found if you have a short or and open circuit you can track down where it is! You can do the same tests from the plug near the glove box that has the temp sender wire on it to determine if the problem is closer to the engine from that plug or closer to the dash.

I hope that was of some help!

Cheers
Wilbo

[Gibbon]

Thanks - Wilbo

Do you think this might be the problem



Don't know how it came loose, but reconnecting and the gauge works again. I wouldn't have thought about looking behind the glovebox without your suggestion.

[wilbo666]

Good to see a happy, and somewhat easy ending!

Looks like you went about solving the problem really well! Also good to see a conclusion as well!

Cheers
Wilbo

[Rorge]

I'm bringing this thread back from the dead.. I've got the same issue atm except the person who did the original conversion on this car has left cut wires left right and center!

I got under the dash and found the plug in the pic... and all the wires are currently detached.. It looks like 2 of them were actually connected.. So essentially i need to find out what colour the wire for the temp sensor is from the 1jzgte ECU so i can tap in there...? (or will this change the resistance too much?)

[EldarO]

look for the yellow wire with a green stripe through it, connect those two sides up and your temp on the dash should work.

Elmo.

[wilbo666]

look for the yellow wire with a green stripe through it, connect those two sides up and your temp on the dash should work.

Elmo.

I'm going to make it a little more complex than that...

Find the wire that goes to the 1JZ temp sensor. This can be done using a multimeter, put one end of the multimeter at the 1jz temp sensor wire [Unplugged], and then use the other end of the multimeter to find that wire inside the cabin on the ECU loom. That way if there is more than one yellow wire with green strip you'll have no issues

The MA61 body side should be a yellow-green wire too (you can always trace that back to the dash).



Cheers
Wilbo

[Norbie]

In situations like this I often end up running a new wire from the sensor to the dash. No chance of confusion then!

[wilbo666]

In situations like this I often end up running a new wire from the sensor to the dash. No chance of confusion then!

Bah, but no neatness!

Brute force, no elegance!

While the norbie approach works, it is a bit medieval

Cheers
Wilbo

[EldarO]

I'm going to make it a little more complex than that...

Find the wire that goes to the 1JZ temp sensor. This can be done using a multimeter, put one end of the multimeter at the 1jz temp sensor wire [Unplugged], and then use the other end of the multimeter to find that wire inside the cabin on the ECU loom. That way if there is more than one yellow wire with green strip you'll have no issues

The MA61 body side should be a yellow-green wire too (you can always trace that back to the dash).



Cheers
Wilbo

yellow green is temp guage, the only wire ive ever confused with it is yellow black, oil pressure, and this was in poor lighting

not too hard, just spend some time looking and studying, then it hits ya and you go "OHHHHHHHHHHHHHH THATS HOW IT WORKS?!?!"

Elmo.

[Rorge]

THANKYOU THANKYOU THANKYOU!

1 wire! It was so freakin simple!