My '77 C/W has had the original rally gauges replaced with aftermarket units (the original cluster probably crumbled to pieces). Problem is, the factory harness is gone after the pigtail, and whoever did it did the crappiest, gooniest job with the wiring. Naturally, nothing works, except the temp gauge which is mechanical.   

I can't find a wiring diagram in any Haynes or Chilton manual, and even the 1977 Ford Car Electrical manual (the one that looks like this: http://www.faxonautoliterature.com/Assets/ProductImages/1977FordCarORMSet.jpg) is devoid of any schematics.

Anyone have a line on some wiring diagrams for this thing? I'd appreciate it so!

Thank you, Mike, for finding that. That one's got the schematics? That may be the route I have to take. I was so hoping to avoid having to make yet another ebay purchase and wait for yet another thing in the mail... I don't suppose someone has some pdfs or scans they can post...? 

Must be an add on that someone put in, all I have is the Idiot light..

Aftermarket gauges commonly do not wire up like the factory instrument wiring harness will, you go your own way there. Far better to wire your own but as you see you need to know what you are doing. Anyone knowing needs no schematic..... .............. .no insult intended at all but the way it is. Like they say, refer to individual product website and then put all together to make your own harness, what you are going to end up doing anyway.

On late Pinto the water temp light and oil pressure light are one and the same.......... ............'engine' light.

Should do same with oil pressure, electric OP sucks......... ........

I mentioned this before elsewhere but Autometer has a nice inexpensive mechanical oil pressure and water temp set. First thing I installed in my 73 after I got it.
d=" class="bbc_link" target="_blank">http://www.jegs.com/i/Auto-Meter/105/2392/10002/-1?parentProductI d=

Wow... I haven't checked in to the forum for a while and didn't even notice that this thread got bumped! Right on. And as it happens, I've come back to this gauge issue.

To those wondering about why there are gauges in the first place... this car is a Cruising Wagon, which came from the factory with the rally gauge package: A tach next to the speedo, and three gauges in the center of the dash above the radio: fuel, temp, amps. (The heater controls are below the radio in a little consolette thing.)

Of course the plastic case the gauges were built into tends to disintegrate and turn into powder over time, which is probably what happened when someone before me switched them out with Auto Gage units (Auto Meter's cheaper cousin). They were old and the job was so hackneyed, so I started over with a brand new set. A mechanical oil pressure gauge is now included, with the fuel gauge off to the right.

amc49, I see the point you're making and generally agree. However, in this case, I'm trying to take advantage of wiring that already exists, especially since I don't want to add more wiring to an already messy situation. I know I'll have to make my own harness, which isn't a big deal, but since I'll be using the factory fuel sender, and there are already wires present for the fuel sender, ammeter, lights, ground etc., I don't see the sense in starting completely from scratch. That, and running wiring is a pain in the @$$

Sorry to bump such an old post but I recently purchased a '79 Mercury Bobcat.  It has the rally dash gauges and where the harness mounts has crumbled.  Do you happen to remember or have a wiring diagram for the harness so I can try to wire some other gauges up?