jwillman

I just did a pod hard wire mod. Everything is working except the speedometer.

The speedometer had worked before but odometer had never worked so I replaced it while in the pod.

I have triple checked the wiring at the pod and am now working on verifying signal to the speedo.

I have read some other posts about checking for speedo signal pulse. Can I jack up the rear of the car, start and run the car in gear to check for signal at the pod connector brown/ red signal wire? What am I looking for, pulsing 12 volts?

Is there any way to test the speedo itself?

Thanks

WICruiser

You are the right track but you only need to rotate the rear tire by hand and watch for the voltage to make/break. I would start with the connector in the spare tire area (1 should be steady voltage and one should switch from voltage to nothingas you rotate the tire) and then go to the central wiring unit before going to the pod connection.

I am fighting a similar problem but have confirmed that I have a voltage make/break from teh sensor but I have a significant voltage drop such that I am only getting 8 volts at the connector in the spare tire well.

The edge connector on the pod is a likely cantidate in my case. I have cleaned a lot of connectors without any influence so my next task is to tighen up the edge connectors.

jwillman

Thanks Roger.

As it was working before I pulled the pod apart I am really suspect of something I did

As I mentioned I have the pod wiring correct. I have not found the spare tire well connector on the wiring diagram. What is the source for the constant power at that connector?

WICruiser

Not sure about the power source on the '79 but I am sure it comes from tCE panel (I know a lot of options there). On my '85 the spare tire well connector is a flat 2 wire connection, in the front of the spare tire well under a fiber board protector. The connections at the CE panel should be numbered on the wiring diagram with a letter (determines the plug) and a number (determines the location in the plug).

I agree the problem is most likely where you worked last. The cluster edge connections can be tough to get good connections because there are so many and each connection needs to make solid contact. I am still owrking on mine to try and get decent contact.

jwillman

I did the pod rewire and replaced the flexvcircuit board with hard wires and molex connectors. I have good continuity for all the speedo wires at the pod. Need to run the car side now.

WallyP

Find Plug H on the Central Electric Panel - Start at left, A. B, C...
Remove the Plug. With ignition switch on, the brown/red wire in H1 (bottom left as plugged in) should have 12 vdc. The brown wire in H2 should have ground.
If both of those are good, an Ohmmeter between the two wires should pulse between zero and infinite Ohms (open to closed). If there is no pulse, check and clean the connector in the corner of the spare tire well.

jwillman

Thanks Wally. I had found your extensive system operations and TS write up in another post and printed it out.

I assume I have the instrument pod connected for this check?

When I did the pod hard wire I ran a cetral ground and power wire to a bus bar I added to the back of the pod and have all grounds and power running from that bus bar.

Is the power wire to the speedometer the only power source for the whole system?

WallyP

Yes, the system should be fully connected (except for Plug H, obviously). Check the wire harness, not the Central Panel plug socket.
Original power is from the black/red wire on Terminal 8M.

jwillman

With the panel connected I am getting battery voltage to the guage but only seeing ~5V at H1. Checking voltage at the signal pin on the speedometer it is also only showing 5V.

Should I see system voltage coming out of the guage?

I did hardwire the pod and all other functions are working. Speedometer worked before I started the project. Odometer did not. When I did the hardwire rewire I did not replicate every pin for power and grounds but rather ran one power and one ground to a bus bar mounted to the back of the panel. I have good continuity of all wires to the pins that insert into the guage. I reused the fiberboard block with the pins that insert into the speedo and soldered wires to those.

I also had the speedo apart to replace the odometer gear. Did I screw up something? If so any ideas on what to look at inside the speedo?

LT Texan

HOLY CRAP!!!! That's a lot of work!!!!!

And only one thing wrong?

Fogey1

Got links?

jpitman2

Bullet fuse contacts???? After seeing a spark at my fuel pump fuse when jumpering the relay, anything is possible. And boy did mine go well yesterday, with a bunch of blade fuses in several places!

jp 83 Euro S AT 54k

jwillman

here you go. Thanks WallyP!!

https://rennlist.com/forums/928-foru...no-workie.html

jwillman

Bump. any ideas?

WICruiser

I am following along because I am in a similar situation but in my case it is 8 volts. I pulled my CE panel and it really didn't look to bad but I tried to clean everything but when I put it back together it was exactly the same. I have not gotten back to it for a few weeks now but now that March is right around the corner I want to get this and some of my other winter projects done before they start detracting from my summer driving season.