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Not sure where to start - electrical issues


New Member
Greetings all. I restored my 66 coupe 15 years ago and used VMF to help with some issues back then.
Joined here several years ago but just lurk and read some threads now and then.
I have been able to do almost everything to the car without being stumped until now.
Hoping to get some help from the community here.

My wife and I took the car out last Saturday for a couple hours and about 120 miles. Everything was flawless.
Put the car away and covered it up at the end of the day.

Yesterday, I realized that I left something in the car and uncovered it to retrieve my items.
I noticed that the courtesy light was on under the glove box before I opened the door.
Sat in the car, closed the door and confirmed that both were shut tight.
Checked the door switches manually, and the light stayed on. Removed the bulb for now.
Started the car, let it run for a few minutes, went to turn it off and the car stayed running with the key out.
Car shut off 15 seconds later. Went to restart it and it was dead, but sounded like the starter was trying to engage with the key out.
Removed the negative battery cable. Charged the battery for awhile today, went took hook up the cable and there was a pretty good
sized spark. Attached the cable, no sparks, and started the car fine.

The instrument cluster gauges are now all pegged to the right with the key on or running.
Not sure yet if there are other issues.

Ideas / suggestions on where to start.



Well-Known Member
Staff member
Gauges pegged means there's a ground path on each sending unit line; very strange indeed if all of them peg.
Your courtesy lights could have been on initially if the headlight switch was rotated all of the way to "ON".
If the car stays running with the key out, your ignition switch is likely faulty.
There's nothing that stands out to account for all of your issues, but what you describe is not good. Until you trouble-shoot your wiring, I suggest you continue to disconnect the battery.


The NorCal dude from Belgium
Same here ! Until you trouble shoot your wiring.......DISCONNECT THE BATTERY !!


Active Member
Do check the light switch position for interior lights on.
Check your grounds for connections and cables for internal crud. May help with gauges pegging right, path of least resistance to ground.
The ign switch may be part of the fault as the starter sol on the fender. A part sticking keeps power to coil.


Burning Fossil Fuels at c2
Stick with it and keep posting/asking questions. We've got some really smart electrical people here (not me).



I Don't Care. Do you?
If you don't know the age/condition of the headlight switch I'd swap it out. So many issues always start there. It's not expensive or hard to change. Having that courtesy light on can really only happen if the headlight switch is powering it (given the door switch(es) are operable). You're going to need an electrical meter to sort stuff like this out. Good suggestion to start inspecting ground wire connections.

Mach1 Driver

Active Member
This is an odd set of problems, but it definitely sounds like more than one. Everyone is right that the courtesy lights can only come one from three sources- the two door switches or the headlight switch rotated to on (not pulled out). Below is a schematic for a 69, but yours operates the same way. The lights are on the left and the gauges are on the right of the page. As far as the gauges go, it could be a faulty voltage regulator. Its unlikely that the resistor wire would short.
It is possible that a loose wire shorted into the courtesy light circuit. To test for that take the fuse out that runs the lights. On a 69 it is the only 14A fuse. On that side of the fuse block is a 30A at one end, a 4A in the middle and the 14A at the other end- at least on my 69. Maybe someone with a 66 can pipe in here. If removing the correct fuse makes the lights go out, then it isn't a short caused by a loose power wire. Terry is probably right and its a defective light switch.
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New Member

Thanks for the suggestions. I have not had much time to look at it. Will be getting to it all tomorrow.
I did have time to replace the solenoid, and the key now shuts the car off every time. The slight buzzing noise I heard under the hood seems
to be gone also, and there is no spark when I connected the battery terminals. Will continue to monitor that. Battery remains disconnected.

The headlight switch was replaced when we did the car 15 years ago. The switch doesn't get used much as we only drive it during the day.
I do use it when pulling into the garage at times. It wasn't used last time out.
Will check that also.

I haven't been able to check the door switch on the passenger side
yet, as the car is in the garage and that side is tight. I read that the nut on the back of the ignition switch can cause weird problems if it's loose.
One the list to check also.

The gauges are still pegged (as expected), but should they remain pegged with the key off? They only return to 0 when the battery is disconnected.

I have read many posts on a few forums on testing the CVR and will be doing that also.

Is anyone familiar with this outfit and this product?

I am not afraid to test everything out, just a little unsure of how to so I proceed slowly, and not as flexible as I was when I restored it.

Thanks all


I Don't Care. Do you?
I somehow must have missed where you wrote there was a buzzing noise under the hood. Failing solenoids of all kinds are notorious for such a symptom.

That CVR is probably a modern electronic style unit as opposed to the original mechanical. If so, it is a good upgrade.


Well-Known Member
Staff member
Your gauges are powered by ACC (not fused) so whatever is grounding all of them requires ACC power. The fact that they go back to zero when battery power is removed says that they are receiving ACC power, which only comes from the ignition switch. So what can ground all three gauges? One of the gauges is not sitting correctly in its pod, so that one of the sending line posts is touching the metal case (ground) or your cardboard insulation pieces are missing under the nuts that hold the gauges in place. All three gauges are connected via the CVR power and each gauge has very little resistance within it. Thus, if one gauge gets grounded, the other two can also appear to be grounded. So...you have 2 problems: why are you getting ACC power to the dash with the key off but battery connected (bad ignition switch most likely), and grounded gauges.