Learned a few lessons this weekend, of course the hard way!
Temp Gauge not working.
Grounded sending unit - Gauge rises slightly but not all the way.
Fuel gauge working fine (so not the voltage limiter).
Must be the Temp Gauge.
Let the work begin:
Removed Negative battery cable (a must)
Removed steering tube cover on dash and loosened up bracket to drop the steering wheel just a bit (very important step to a successful non scratch the **** out of everything repair).
Covered the steering wheel tube with a thin towel (see above scratch the **** ....) between the dash and the tube.
Removed the four screws from the Dash unit and carefully pulled it out and past the push buttons then tipped ever so slightly to access the alternator gauge wires. Took lots of pictures! Circuit board wiring harness, etc. Removed alternator gauge wires with 3/8" open end.
Then the hard part, removing the printed circuit board connector (60 years old at that!) that would not budge from the pins. After about 20 minutes of nerves, pulling ever so gently and prying with a screwdriver ever so gently (while avoiding the traces at all costs) and not getting it to budge, I utilized an approx. 1/4" dowel which I shaped into a pencil at the tip and a tiny brass hammer to slowly tap underneath all the way around (dowel was a little bigger than the space between the circuit board and the connector so pencil/dowel worked like a wedge) finally success! Dash was free and clear of all wires.
Slowly removed cluster by going to the right in direction and avoiding steering wheel.
Once removed placed upside down on padded work bench and again lots of pictures documenting where everything goes. Proceeded to take cluster apart, clean lenses, pins for connector, new bulbs, etc. and installed NEW TEMP GAUGE!, Yeah! Looks great flawless rebuild.
Now back to the car. Re-installed the cluster being careful with push buttons, proceeding slowly and patiently in revers order of the removal, Voila! Back to normal.
Lets test before final assembly, screws and steering wheel tube tightened. Now the big moment!
Same ****! Temp gauge don't work! WTF!
Back to the drawing board:
Ground the sending unit same result as before rises a little but not all the way as it should. WTF!
Back to the Service manual. Now I must have read this section a million times and somehow still missed the part on grounding your test lamp to the sending unit and you should see a pulsing light, how I don't know!
So I ground the sending unit and sonofaB no pulsing light! Huh. So I go to the firewall wiring harness clip and put my tester on the same wire. Success! We got a pulse, hmmm, on to something. Must have a break in the wire somewhere between the sending unit and the clip on the firewall.
Sure enough about 14" from the sending unit under the wire loom material there was a break in the wire. Fixed the wire and finally Success!
Unbelievable.
So if I can share and help someone else it will have all been worth it!
If Temp gauge isn't working:
Ground the sending unit first. Gauge should slowly rise to full hot (don't ground any longer than that).
If it doesn't, use a light and ground the sending unit and light should pulse on and off. If it doesn't check same wire at the firewall connector.
If it doesn't pulse there either it is most likely the voltage limiter on the printed circuit board.
If it does pulse there is a break somewhere between the harness connector and the sending unit. Find and fix.
Job done!
Hope this helps. And that I didn't forget anything.
Jeff
Temp Gauge not working.
Grounded sending unit - Gauge rises slightly but not all the way.
Fuel gauge working fine (so not the voltage limiter).
Must be the Temp Gauge.
Let the work begin:
Removed Negative battery cable (a must)
Removed steering tube cover on dash and loosened up bracket to drop the steering wheel just a bit (very important step to a successful non scratch the **** out of everything repair).
Covered the steering wheel tube with a thin towel (see above scratch the **** ....) between the dash and the tube.
Removed the four screws from the Dash unit and carefully pulled it out and past the push buttons then tipped ever so slightly to access the alternator gauge wires. Took lots of pictures! Circuit board wiring harness, etc. Removed alternator gauge wires with 3/8" open end.
Then the hard part, removing the printed circuit board connector (60 years old at that!) that would not budge from the pins. After about 20 minutes of nerves, pulling ever so gently and prying with a screwdriver ever so gently (while avoiding the traces at all costs) and not getting it to budge, I utilized an approx. 1/4" dowel which I shaped into a pencil at the tip and a tiny brass hammer to slowly tap underneath all the way around (dowel was a little bigger than the space between the circuit board and the connector so pencil/dowel worked like a wedge) finally success! Dash was free and clear of all wires.
Slowly removed cluster by going to the right in direction and avoiding steering wheel.
Once removed placed upside down on padded work bench and again lots of pictures documenting where everything goes. Proceeded to take cluster apart, clean lenses, pins for connector, new bulbs, etc. and installed NEW TEMP GAUGE!, Yeah! Looks great flawless rebuild.
Now back to the car. Re-installed the cluster being careful with push buttons, proceeding slowly and patiently in revers order of the removal, Voila! Back to normal.
Lets test before final assembly, screws and steering wheel tube tightened. Now the big moment!
Same ****! Temp gauge don't work! WTF!
Back to the drawing board:
Ground the sending unit same result as before rises a little but not all the way as it should. WTF!
Back to the Service manual. Now I must have read this section a million times and somehow still missed the part on grounding your test lamp to the sending unit and you should see a pulsing light, how I don't know!
So I ground the sending unit and sonofaB no pulsing light! Huh. So I go to the firewall wiring harness clip and put my tester on the same wire. Success! We got a pulse, hmmm, on to something. Must have a break in the wire somewhere between the sending unit and the clip on the firewall.
Sure enough about 14" from the sending unit under the wire loom material there was a break in the wire. Fixed the wire and finally Success!
Unbelievable.
So if I can share and help someone else it will have all been worth it!
If Temp gauge isn't working:
Ground the sending unit first. Gauge should slowly rise to full hot (don't ground any longer than that).
If it doesn't, use a light and ground the sending unit and light should pulse on and off. If it doesn't check same wire at the firewall connector.
If it doesn't pulse there either it is most likely the voltage limiter on the printed circuit board.
If it does pulse there is a break somewhere between the harness connector and the sending unit. Find and fix.
Job done!
Hope this helps. And that I didn't forget anything.
Jeff
