Jumping the 72 somehow wrecked my gauges - QUESTION

[j1mblack]

Hey gang, I left the lights on one day in the mach 1, like an *****. Called triple A to have it jumped, guy brought a power pack and fried the starter solenoid. Had to get it towed. Bringing it back I noticed the gas gauge, oil, temp, and blinkers all stopped working - except for the back blinkers and hazard they work fine. The HVAC system switches and radio also have went, but I have my front lights horn, and tachometer still.

What could've possibly happened to cause this? Too much voltage from the power pack? I've replaced the alternator regulator and starter solenoid. Those gauges had been working before and I had just replaced them. Could this have possibly blown all these sending units?

I've replaced all the fuses as well and I'm going today to get two flasher fuses, as well as a TRS switch later this week.

Here's the history on the car, I haven't really shared anything with yall on it, but I've documented all of the replacement parts we've done. Well needed rubber repairs, gaskets, valve stem seals, timing chain, all electric, battery, radiator etc.


Came from Johnny Harper Ford out in Colorado, made in 71. 351C 2 banger originally upgraded to the 4 to sneak by that emissions law. FMX tranny, bigger rear end, black interior. Had her shipped from South Dakota to the east coast. 60K miles. Restored the engine back to spec (not concors) but it was my first engine rebuild basically. Body was in great condition except for the trunk edge rust (tiny bit). Here's how I have the engine bay set up.

 

[Doug's 73 Mach1]

There is a "constant voltage" control mounted on the back of the main gage cluster that may have failed. It controls the fuel, oil and temp gages. Perhaps the jumping was done with the polarity reversed (+ to - and - to +, verses + to + and - to -) , not sure that would cause the problems you describe.

 

[cv_72mustang]

I believe what may have happen was a load dump event. This event is caused when the battery terminals are loose. The alternate 'sees' a change load/inductance and voltage regulator can't respond fast enough. I've seen just adding the jumpers cables can force batteries post to loose up. Course a defective jumper pack might be the culprit also depending on the failure. Maybe! The newest jumper packs should have reverse connection safety feature.

 

[j1mblack]

There is a "constant voltage" control mounted on the back of the main gage cluster that may have failed. It controls the fuel, oil and temp gages. Perhaps the jumping was done with the polarity reversed (+ to - and - to +, verses + to + and - to -) , not sure that would cause the problems you describe.

thanks for the replies everyone, I'm gonna give this a try cause thats exactly what went.

 

[j1mblack]

Gang I actually figured it out. The ignition that we replaced when pushed too forward somehow turns the gauges off/causes a short? Must have installed it wrong. When I turn the ignition fully on and locked as far as it can go the gauges will stop working. Pulling back like an 1/8 of a turn all the stuff works including the radio and HVAC.

 

[basstrix]

Here's the adjustment procedure from the Ford manual. It's possible the switch is adjusted such that it can end up partially into the Start position and isn't getting pushed back to the run position. The new switch should have had the pin, they mention, already inserted,