IPVR Question

[LuvMyScamper]

Hi Guys:

On a '71 F350, is it normal for the IPVR to cause the dash lights to pulsate? I know the IPVR is supposed to send 5 volt pulses or something like that for the gauges to work, but would this affect the dash lights too? I'm starting to wonder if the IPVR is going bad. I have full gauges, and the oil pressure and coolant temp gauges work, but the fuel gauge and ammeter gauge do not work. I'm going to go out with my multimeter today and do the troubleshooting for the fuel sending unit in your tech section. I also read that there is supposed to be in-line fuses that go from the alternator and the solenoid to the ammeter. I'll check those too. If those all test normal, is it safe to assume my IPVR is bad?

TIA,

Cindy

[LuvMyScamper]

Troubleshooted the fuel gauge...it's the sending unit that's bad. The wiring was bad too, but once I corrected that and re-did the test by grounding it to the housing the gauge pegged on full. The gauge actually moves a little bit now - it moves up to the empty bar but I know there's about a 1/2 tank of gas in it so the sending unit has to be bad.

As for the ammeter, I looked for those inline fuses I read about but I don't know what they look like and just got frustrated the more I looked for them so I'm just going to forget about the ammeter.

Cindy

[Thunderfoot]

The dash lights are not in the circuit with the IPVR... Flashing/pulsating dash lights is a sign of an Alternator or Voltage Regulator problem... Usually from a bad diode in the Alternator...

The Alt gauge in these trucks doesn't work very well, you will see very minimal movement of the needle under normal conditions and maybe 5-8 needle widths movement when you have a week battery (movement towards +) or dead alternator (movement towards -)... The inline fuses are on the passenger fender in the wiring harness by the alternator and starter solenoid, they are just normal "inline" fuse holders... like in this picture.

[LuvMyScamper]

Thanks for the reply. We just replaced the alternator a couple of weeks ago with a new one but did not replace the voltage regulator. In hindsight we probably should have done both as it looks pretty old.

Cindy