Calmchaos

I have replaced the sender at the transmission with a new one, and I have replaced the gauge cluster. All other gauges work fine.
What do I do now?
Does anyone know if the speedometer is run through the DME wiring harness at all?
I'm pretty sure it is not, but I'm not 100% on that.

Need suggestions... badly.
Thanks

Calmchaos

really???
....bump...

Jay W

My guess is to check for a broken wire between the sender and the gauge pod. I don't know if it runs through the DME.

Calmchaos

I couldn't see any by inspection. Does anyone know exactly how the wires run through the car? Anything I can test with the multimeter?

Calmchaos

I ordered a new pinion that drives the speed pulse sender. So I'll see if that somehow helps.
Please keep suggestions coming because I'm completely confused.

tinklybear

Check the wiring diagrams in the FSM

Calmchaos

I have the diagrams but I'm not really all that good at reading them, I'll post them up tonight if someone can help me out.

dave1192

The wiring diagram for my 86 NA says there is a Positive voltage connection from fuse 11 (area D6 of drawing which connects to area D17) to the transmission pickup. The other wire from the transmission pickup goes back to pin 14 on the instrument culster connection plug and from there to the speedometer. Maybe the fuse is blown?

Calmchaos

I checked the diagram and I think you followed the first line wrong, I think the fuse is fuse 18 for the instruments. Follow the line again and see if you agree with me, because, again, I'm not good at these things.

But I went out just now and checked fuse 11, and 18 and they were both fine.

If you follow the line and get to fuse 18 were I did, could you explain what all the stuff around that fuse means for me?

I REALLY REALLY appreciate the help!!
Oh... also... the speedo is the ONLY gauge that doesn't work.

JohnKoaWood

it is fuse 18,
I assume you have checked your grounds?

Using a multi meter check for continuity between the sender pins, 1-2 should be connected, neither should be connected to Pin3

MP II is the grounding point for the speed sensor, attached at the firewall. Use a multimeter to check Pin 3 of the harness connector at the speed sensor to the body of the car, value should be small,if not, your ground is bad.

Next check Cluster Pin 14 to Pin 2, this would be the ground signal from the gauge cluster to the connector, if value is near 0 (use diode test on multimeter for tone) it is good.

Next Pin 1 to pin 4 of the instrument cluster, this is the + signal to the sensor, if this is good, continue..

If everything above is good, your problem is not the wiring, it is either your gauge, your sender, your relay, or a loose connection on the harness that you will have to wiggle wires to eliminate.

Good Luck...

JohnKoaWood

Not sure what you are asking for? E7 block is a reference to another page of the wiring diagram, look around the border and you will see leters and numbers, now find the page with coordinate E7, you will see a block labeled F18 (its on page 1 by the way).

The bold dashed black line the the relay central electric panel (fuse and relay block). This is where fuse 18 is located. if you follow the wire up the page (on page 4) you will see a diamond (I19) this connects to the wire (pin 4 of the cluster) also showing the same I19 diamond (above and to the left on page 4).

Is this what you were looking for?

Calmchaos

Amazing information thank you!!
Except I'm not sure what a diode test is on the multimeter.

JohnKoaWood

It should beep when there is continuity.

fortysixandtwo

I didn't see this answered.
The speedometer wiring does not integrate with the DME wiring, neither physically or electronically.

Calmchaos

Thanks forty... I just built a DME harness and was 99% sure but I wanted to be 100%.
And to john... I don't have that on my meter (I have a cheap one) will I be able to test without that mode?