country4x4

I need some help here, I've got the 86 F150, and I'm realizing now that ONLY my speedometer works (after I cleaned the mud dauber nest out of it)

I'm thinking its a bad positive or ground somewhere because my switch controlling the heater/fan also doesnt do anything or appear to get power according to my volt meter.

is there a common positive/ground I need to look at? I could give 2 craps about the fans, but it'd be VERY nice to know my charging voltage, and for SOME reason knowing how much fuel I've got is really nice.... not sure why.

Edit : google has revealed a little cluster voltage regulator on the back of the cluster that MAY be the source of my woes. I'm praying it is. if so, anyone know where to get another one?

klricks

Here is an IVR:
http://www.autozone.com/autozone/par...mString=search

Note that the Instrument VR only runs the Fuel, Oil, and Temp gauges and nothing else.
I would do some more troubleshooting before just replacing parts. Check fuses, Check voltages to the IVR etc.

country4x4

for the regulator, if I knew the specific voltage and ohms required, I could VERY probably pick up something at radioshack for far less. I suspect this to be the problem, but I'm gonna do some tests to confirm before I go throwing money and parts at it.

I dont doubt that I overlooked an obvious fault. but I have no idea.

klricks

The IVR is not just a simple resistor. Inside there is a bi-metallic switch like an old style thermostat. It pulses on and off every half a second resulting in a measured average output of about 5VDC. The 'duty cycle' output varies depending on the load. The load changes depending on the resistance of the 3 senders attached.

Here is a diagram showing the internals of the IRV. Notice the resistance wire feeding the IRV has some voltage drop.
Check the voltage there at that wire. Should be maybe 10 or 11 volts. If not you may have other issues such as a bad wiring, ignition switch etc.

http://img407.imageshack.us/img407/5...ankdiagram.jpg


One guy on another forum attempted to make one using a 3 terminal voltage regulator. I am not sure if he was successful? The thread went off in all directions... there is some photos of the insides of the IVR etc.
http://www.ford-trucks.com/forums/11...ing-gages.html