Gauge wiring

[71 LONG BED]

I started wiring the pigtails for my F750 gauges. The wires were a butchered mess. I got it pretty well cleaned up. I know were each wire goes, so I thought. There is a small square piece that has one wire connected to it and a blade for another connection. After unwrapping some electrical tape from some loose wires I found another wire with a connector similar to the one already connected to the mystery square thing. Funny thing is the connector had a wire taped to the connector and was hanging, not being used.
My questions are, what is the small square thing and what should be attached to it?

The red arrow is pointing to the blade that has nothing attached.

[FORDification]

That's the IPVR (Instrument Panel Voltage Regulator). It's basically what converts the 12V power to 5V pulsed and is what powers the gauges. (Don't hook 12V power up to those gauges, or you'll fry 'em!) Here's a couple pics I just shot of the F600 panel I just happen to have sitting by my desk:





The wires going to it are black with a green stripe. As you can see there's also a black ground wire with a bullet connector that grounds to the instrument panel itself.

[71 LONG BED]

Don't hook 12V power up to those gauges, or you'll fry 'em!

I was going to solder the pigtails to the corresponding pins on the plug of my harness. I have a '71 so I can trace the circuit back to the plug. I was going to ground the black wire and just hook up the positive side of the gauges to the plug in the harness. Will that work that way? Right now I only have one wire connected to the IPVR were does the other side connect to?

[FORDification]

heh...since I KNEW you were going to ask that, as soon as I posted those pics I dug out an Exacto knife to slit the wiring harness wrap and trace those wires. Stand by....

[71 LONG BED]

Cool, thanks Keith...

[FORDification]

OK, here's a quick diagram I just whipped up of the F600 instrument panel connector:



Position 1 - black - IPVR ground
Position 2 - light green w/white stripe - left turn signal indicator
Position 3 - orange - fuel gauge (FULL side)
Position 4 - black w/green stripe- IGN tab of IPVR
Position 5 - white w/red stripe - oil pressure gauge (high side)
Position 6 - light blue w/red stripe - gauge illumination

Position 7 - NOT USED
Position 8 - white w/blue stripe - right turn signal indicator
Position 9 - green w/black stripe - hi-beam indicator
Position 10 - red w/white stripe - temperature gauge (high side)
Position 11 - yellow - ammeter (charge side)
Position 12 - red - ammeter (discharge side)

So....to answer your question about which wires to go the IPVR:

There's a black wire which comes from Position 1 in the connector to the IGN tab of the IPVR. A black wire w/white stripe goes from the opposite IPVR tab to the EMPTY stud of the fuel gauge, which then goes to COLD side of the Temperature gauge, which then goes to the LOW side of the oil pressure gauge.

Here's a view taken after cutting the harness wrap.



You can see how the black wire w/white stripe goes from the IPVR to the fuel gauge (yellow '1'), then to the temperature gauge (yellow '2') and then across the instrument panel to the oil pressure gauge (not visible).

Hope this helps.

[68F250]

Excellent posts Keith! Very informative. Well done!

John, I think you owe Keith a six-pack. Mountain Dew

[shanmeg1]

Send him a hoagie or steak sandwich. John

[71 LONG BED]

WOW, thanks a million Keith!! I had to hit the hay last night, so I am catching this from work this morning. I'll have to take a closer look from home tonight. I'll bring my panel up to the computer from the garage and compare.
Again, thanks a million!!

[71 LONG BED]

I hope I get this. I have the black wires that jump from gauge to gauge, I guess the other side of the IPVR goes to the plug. Is that wire a ground? I could just send it to a ground in the plug on the truck.
The problem is I only have one side of the plug that belongs to the gauges, so I can't use it. I want to solder pigtails to the existing plug that is on the truck and send them to the posts that they belong to.
Nothing is ever easy! I would have to get gauges that were butchered!
I'm having trouble concentrating on work thinking about this! I want to get it figured out now, I can't wait until I get home.

[FORDification]

Tell you what, don't go doing this haf-ast....you'll regret it in the long run. I've got a couple junkie instrument panels in the shop I was going to use for parts (if I needed them). I'll just snip a end off and send it to you. PM me your mailing address.

[lobuck76]

I wired up the f600 guage panel in my '71 today.
All the wires matched up exactly except for the black w/green stripe. The wire that goes from the ign, switch to the IPVR on the '71 was purple and looks like a resistor wire.
I soldered the black w/green stripe to the copper connector on the purple wire. Kieth if that's wrong you can chime in!
Iv'e got add on oil press. and temp guages. So I'll need to get the factory sending units back in to tell if the guages are going to work ok.
The fuel guage read a quarter of a tank higher than it did before the guage panel swap. I'm going to go fill it up with fuel shortley and see how it reads.
Also my truck had factory guages and not idiot lights.

[Dropped 68]

I ran into the same thing in my '65 when I first got it, the fuel guage nor the factory oil pressure guage worked. So as a process of elimination I hooked up a temporary 12 v hot wire to both guages to see if the guages themselves were bad. they both worked just fine with the exeption that they both pegged out at max. Then after some research I found out about the resistor that cuts down the voltage. Found one out off another truck and I was good to go. If I remeber correctly one side recieves 12 v in and the other supplies hot power to all the guages. So even if your guages wouldn't fry they certainly wouldn't be right without it. hope that helps some.

Charles



Hit the switch, drag that ****!

[FORDification]

Charles: You're very lucky you didn't fry those gauges....the IPVR reduces the steady 12V to a 5V pulse, so if they're still working, count yourself very lucky.

lobuck: I don't have any '71 wiring diagrams for the site yet, but the '72 diagram does show the purple wire as a resistance wire which is spliced into the green-red wire which extends from the voltage regulator to the instrument panel plug. However, I can't tell from the wiring diagram which wire in the connector that is. However, the Ford truck wire chart does show Circuit 30 as a black/green wire going from the ignition switch to the IPVR and indicator lights. So...based on my limited knowledge of wiring and simply trying to follow along on the wiring diagrams, I'd have to say you've probably got it right. You'll have to let us know once your gauges are hooked up whether that's correct.

[lobuck76]

I got the sending units installed this morning and the guages seem to work fine.
I printed the above diagram and traced the wires from the plug to the guages on the printed circuit , that'l make you go crosseyed!