1965 Comet Gauge problem

Ron61 · #1 (**permalink**) 01-13-2005, 08:55 AM

Ok, about a month ago when I went out to start my 1965 Comet, all of the gauges on the dash didn't read until about 20 seconds after the motor was running and then they all started working. Now this is the gas gauge, temp. gauge, oil pressure, and also the windshield wipers and heater fan motor won't run until they kick in. The amp gauge just twitches back and forth and it used to be steady. I have replaced the regulator, checked what grounds I can get to without spending hours out in this cold, and haven't found the problem. I think it must be a loose ground, but since I can't find a wiring diagram anywhere around here for that old car, I will ask here. First the heater fan and wipers run off different fuses than the dash gauges, so that elimates a fuse. The battery is never down or drags when I start it cold in the morning. Could this be an alternator problem? I can't figure out why the amp gauge has started that bounching around after this started as it never did it until now. And it will show a charge if I let the lights draw the battey down some. Also at times it will just suddenly go back to being steady like it should. I am almost certain this has to do with a loose wire or ground, but since I have no wiring diagram, I don't know what would be common to all of these things. And blipping the throttle seems to make everything come on faster when I start the car. Almost as if the movement of the motor may have made a wire contact. Once they start reading they will read until I shut the engine off.

Thanks,

Ron

392cobra · #2 (**permalink**) 01-13-2005, 09:04 AM

Ron,
Just a thought. How about your ground from the engine block to the firewall.
What are your headlights doing at the time the amp gauge is twitching ?

Ron61 · #3 (**permalink**) 01-13-2005, 09:13 AM

Fred,

The headlights are just as steady as they can be. This is just a weird problem and I know everything is working. I also watched the dome light and inside lights and they never blink when the amp gauge is twitching. What really messeswith my mind is the other gauges are on completely different circuits from the lights, wipers, and heater fan. I was going out after while and do some more looking but it is getting dark and colder so I will wait. Any more suggestions would be greatly appreciated.

Ron

Excaliber · #4 (**permalink**) 01-13-2005, 10:04 AM

Hey Ron I didn't know you had a '65 Comet. In 1968 I worked for a body shop in Enterprise (one man show at the guys house actually) and helped him repair a "totaled" Comet, 289 four speed. Man how I loved that car. I got to drive it several times before it was sold.

Hey,,,, uh,,,, is yours Gold in color? I think I know that car!

Ron61 · #5 (**permalink**) 01-13-2005, 10:17 AM

Ernie,

This is my daily driver and it is green with a white top. It has a 289/2 barell carb and an automatic. I love this little car and just had the engine rebuilt after 152,000 miles. Needs paint as the parking lot wars have taken their toll.
Now that I know you know about them, I expect some help on this weird problem. It has been going on for a couple of months and doesn't hurt anything, but it is driving me nuts trying to pin down something that could cause all of this. I swear it seems like a ground problem, but what could afect all these different circuits like that. I was going to get under it today and do some looking at grounds but it is to cold and getting darker now. I think I have pretty well eliminated the regulator, (new one), and alternator, but am not positive about the alternator. However I don't see how that could cause all the gauges to not read for 20 or 30 seconds after I start the car and then all of a sudden they kick on. And the ampmeter flicking back and forth like that is weird as it is in series with the alternator and battery and not on any other circuit.

Ron

Sub Note: If I just turn the key on and don't start the car, the gas gauge will read, but the minute I start the car it drops back to zero until all the gauges kick in. Strange HUH !!

flipper35 · #6 (**permalink**) 01-13-2005, 11:00 AM

And I thought the interior lights flashing when I tried to honk the horn in my old Magnum was wierd!

I don't really have anything to offer other than moral support. I would rather track down just about any other problem than an electrical one.

The ground certainly is suspicious. I am assuming the problem is not there on warm starts? Is the voltage steady when the amp gauge flickers?

Ron61 · #7 (**permalink**) 01-13-2005, 11:20 AM

Brent,

I put my meter across the battery and the voltage is steady as a rock. Also proved that my alternator is putting out. This does happen on warm starts, but just doesn't take as long for the gauges to suddenly start reading. Darn, I hate tracking electrical problems worse than anything and especially ones like this that are more or less intermittant. When it warms up enough for me to really dig into this, I may start disconnecting stuff and see if I can get it down to one path or somethiing. Darn factory wiring is all covered and ran down under the engine of course.

Ron

rabbit1340 · #8 (**permalink**) 01-13-2005, 11:53 AM

You said you replaced the regulator, was that the one behind the dash called the constant voltage regulator? That one regulates the voltage to the dash gauges. Ford base part # 10804. You can find them on ebay.

Double Venom · #9 (**permalink**) 01-13-2005, 12:58 PM

rabitt beat me to it! If I remember right there is a 'ballast resistor' looking object on the back side of the dash. Is this what your calling the constant voltage regulator?

If one of those coils or windings has let go, then I can see this as a possibility.

Oh to find a good '65 or '64 with a 260 and factory 4-speed! What a great toy!
DV

Ron61 · #10 (**permalink**) 01-13-2005, 01:17 PM

Ok, dumb question. The regulator that I replaced is mounted up front across from the battery and the new one was bad. I got it out before it fried the battery. Old one is good. Now just where behind the dash is this one that you are talking about located? That sounds as if it could be what I am looking for, but with no wiring diagram I didn't know they had one for the gauges. And no D.V., the regulator that I replaced with a bad one was just the normal 4 pronged one that came on the car and is a sealed unit about 4 to 5 inches square. But the old one is good and back on now and I got my money back from NAPA for that bad one they sold me.
You said behind the dash so I am guessing that it is inside the car and up under there somewhere. Which side of the car would it be on. Drivers side or passenger side?

Thanks,

Ron

Double Venom · #11 (**permalink**) 01-13-2005, 03:52 PM

Ron,
I understand the one you're talking about but the one that we're talking about doesn't look anything like the engine/car regulator.

I'm trying to remember location, definately behind and attached to the gauge pod or back of the dash.

Feet up on the back of the seat, head down, under the dash, good flash light in hand and you should be able to spot it. I'm thinking it was between the ampmeter gauge and the speedometer. 40 years ago was a long, long time ago!

DV

Ron61 · #12 (**permalink**) 01-17-2005, 05:36 AM

Ernie,

Just for you I will try to post a picture of the Comet. If I can't get it in here I will put one in the gallery and link it.

Ron

cobrajeff · #13 (**permalink**) 01-17-2005, 07:01 AM

Ron -

Nice looking Cyclone. My first car was a 1965 Comet Caliente - I had it all decked out with Shelby 10-spokes, side pipes, dual quads, and a Cyclone fiberglass hood.

The Constant Voltage Regulator, also sometimes referred to as the IVR (Instrument Voltage Regulator), is about 1 inch by 1/2 inch rectangle. It is mounted to the printed circuit board on the back of the cluster - and I think DV was right, between the speedo and amp guage. I believe you will have to pull the cluster to service it (which means you'll have to disconnect the speedo and guages).

This part would be the same as one on a 1965-66 Mustang, which will probably be easier to locate than Comet parts. The clusters are the same, only the graphics on the guages are different.

regards,

Jeff

Double Venom · #14 (**permalink**) 01-17-2005, 07:40 AM

Ron, here you go,

It's the small silver part at the bottom. I think it's about $30.00.

Now, for slight nominal fee I will be glad to pick up the part, deliver and install.

You can find it at "California Mustang" on the web

DV

ron427 · #15 (**permalink**) 01-17-2005, 08:35 AM

Ron
The only thing I can think of that is common with the three gauges and the heater fan is 12 volt ign power or ground.
All the gauges except the ampmeter are powered through the constant voltage regulator that is mounted near the center of the instrument cluster. The mounting screw for the regulator usually goes into the printed circuit and provides a ground for the regulator.

The IVR actually provides a "pulsating 12 volts" at the on-off frequency near that of a turn signal flasher and gives an average of about 7 volts. If working properly you should be able to test at the input side of any of the three gauges with a test light or analog voltmeter. Also while in the "failure mode", see if you have 12 volts to the heater motor. If you have a good jumper wire, try running an aux. ground from heater motor or gauge cluster to battery ground. As you probably know, a loose ground can give a conbination of problems you would never dream of. I see no way the regulator can directly effect the wipers or heater.

I am retired and usually home. Call me at 318-343-7158 if I can help.

Nice car and good luck.

Ron Johnson

Ron61 · #16 (**permalink**) 01-17-2005, 10:47 AM

Jeff,

My Comet is the Calientie also. Nice little driver.

D.V.,

After an hour of twisting and trying to see up under that mess, I still can't see anything that even resembles that regulator. But with that darn steel plate they have from the dash to the firewall, it blocks sight of almost everything under there except the speedometer cable. And I am afraid to start reaching up in there to much trying to feel around as I don't want to break any of those old wires which are just going in all directions. Oh, to be 12 years old and about 4 inches high for an hour.

Ron,

Thanks for the offer and I may take you up on it as soon as I can find a way to see any of the backs of the gauges. I think it will mean taking out the defroster vent tubes and other stuff to even see them from the back. And of course I am sure those old tubes will crumble at the first attempt to move them aside.

I will try to get back under there later in the week. I am to old for that upside down stuff especially when I can't even see anything once I twist myself around the brake pedal enough to get on the floor with my head.

Ron