Before I crawl under the dash
So here's the next installment. With the seat out, I crawled under the dash and with my faithful assistant (wife) watching the gauges, the engine up to temp, key in "run", while I wiggled and jiggled the dash unit plug, the IVR, played with the studs and nuts behind the gauges and neither needle even jiggled a bit. So here's my plan of action. Please yell if I'm doing something bad. I won't be able to get back to this for a week.
Here's the wiring diagram for that area:
Question: Do these gauges operate by varying the ground at the sender? If I ground the gauge at the side of the gauge that goes to the sender, or at the wire connection at either sender should the gauge react? As long as this is on the voltage limited (5v) side of the equation, can I fry the gauges? I know how the fuel sender is grounded through the output tube and have installed a nice fat wire from it to the body, but how does the temp sender ground?
Check for 12v to the IVR
Check for 5v coming out of the IVR
Check for 5V at the feed side of the Fuel Gauge (at the post)
Check for 5V in and out of the multiwire plug behind the kick panel
Check for 5v at the plug that connects to the fuel sender
Then:
Check 5v to the feed side of the temp gauge
Check 5v at the plug on the sender
Check 5v at the input and output at the bulkhead connector
Remember all this stuff is new, so no corroded connectors. I assume if there is 12v into the IVR and nothing out, the IVR is bad. If something fails after that, either the new circuit board is toast, or a wire is broken. If there was a grounded wire that shouldn't be, I assume the gauge would be 'up' not 'down'? In the diagram the IVR has a ground but it must ground to the circuit board and I still don't understand how the circuit board grounds, or how the dash unit metal housing is grounded to the body.
Thanks for any further help that you can offer!
So here's the next installment. With the seat out, I crawled under the dash and with my faithful assistant (wife) watching the gauges, the engine up to temp, key in "run", while I wiggled and jiggled the dash unit plug, the IVR, played with the studs and nuts behind the gauges and neither needle even jiggled a bit. So here's my plan of action. Please yell if I'm doing something bad. I won't be able to get back to this for a week.
Here's the wiring diagram for that area:
Question: Do these gauges operate by varying the ground at the sender? If I ground the gauge at the side of the gauge that goes to the sender, or at the wire connection at either sender should the gauge react? As long as this is on the voltage limited (5v) side of the equation, can I fry the gauges? I know how the fuel sender is grounded through the output tube and have installed a nice fat wire from it to the body, but how does the temp sender ground?
Check for 12v to the IVR
Check for 5v coming out of the IVR
Check for 5V at the feed side of the Fuel Gauge (at the post)
Check for 5V in and out of the multiwire plug behind the kick panel
Check for 5v at the plug that connects to the fuel sender
Then:
Check 5v to the feed side of the temp gauge
Check 5v at the plug on the sender
Check 5v at the input and output at the bulkhead connector
Remember all this stuff is new, so no corroded connectors. I assume if there is 12v into the IVR and nothing out, the IVR is bad. If something fails after that, either the new circuit board is toast, or a wire is broken. If there was a grounded wire that shouldn't be, I assume the gauge would be 'up' not 'down'? In the diagram the IVR has a ground but it must ground to the circuit board and I still don't understand how the circuit board grounds, or how the dash unit metal housing is grounded to the body.
Thanks for any further help that you can offer!