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Not sure where to start - electrical issues

LNimoy

LNimoy

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.

Thanks,
John
 
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.
 
Same here ! Until you trouble shoot your wiring.......DISCONNECT THE BATTERY !!
 
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.
 
Stick with it and keep posting/asking questions. We've got some really smart electrical people here (not me).

LLAP
 
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.
 
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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All,

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?

Constant Voltage Regulator Ford Mustang 1965-1966

www.collegevilleautorepair.com www.collegevilleautorepair.com

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 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.
 
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.
 
Thanks for all the suggestions. I finally got back to looking at it after 2 minor knee surgeries and 1 car fire ( daughter's Murano).
I replaced the ignition switch first, and checked that the ACC post only gets power with the key in ACC, Start and Run positions.
I removed the instrument cluster and all the gauges. The gauges are all seated properly into their tabs and are not touching the
cluster base. All the cardboard strips are intact and the nuts for the gauges do not extend over the cardboard strips.
I hooked up the cluster, and the gauges are still pegged. I did get a new CVR, but I am hesitant to install it until I am sure that my problem is resolved.
I don't want to short the new one out and have to buy another.
My courtesy lights are still on with the key removed and the headlight switch turned all the way down.
I removed the switch and tested the switch harness. With the key off, I have power in the harness at the following posts.
B = black/orange wire = battery feed. This is to be expected.
D1 = green/yellow = courtesy feed thru fuse. I assume this is correct.
D2 = black/blue = courtesy lamp. This is hot with the headlight switch removed and the doors shut.
I think that this means that one of the switches in the doors are bad. Opinions!!
Am I correct that I have to remove the kick panels to get at the door switches, or do they pop out by prying the grommet?
My plan was to disconnect them 1 at a time to see if one or the other, or both are bad before going any farther.
I am going to buy an analog voltage meter to test both the old and new CVRs if the other issues are resolved.
Thanks again.
 
Curiosity got the better of me and I went back out to the car again before the rain begins.
With the headlight switch removed, I popped out the two door jamb switches.
With the key in the off position, I have power to all four wires of the jamb switches, two on each side, and to the wire that goes to the glove box light.
Car is back in the garage, battery still disconnected.
Feel free to chime in with anything.
 
The key position will have nothing to do with the courtesy lights. Do you have a volt meter and know how to use it or are you just using a cheap test light? Disconnect the wires from the switches and test to see if they function correctly. When the plunger is depressed there should be no continuity across the switch.
 
LNimoy said:
Curiosity got the better of me and I went back out to the car again before the rain begins.
With the headlight switch removed, I popped out the two door jamb switches.
With the key in the off position, I have power to all four wires of the jamb switches, two on each side, and to the wire that goes to the glove box light.
Car is back in the garage, battery still disconnected.
Feel free to chime in with anything.
Click to expand...
That's bad news. That tells me that somewhere within your wiring someone has jumpered the green/yellow fused power lines with the black/blue courtesy lights. There's no telling where that may be...the door jambs were the most likely place for the cross-feed. The black/blue courtesy lights only get their power when (1) either door jamb switch is pushed out (door open) or (2) when the headlight switch knob is fully rotated. Since you removed the headlight switch and the door jamb switches have been disabled, the problem has to lie somewhere else inside the harness. There is no obvious place to look, believe me...

I'd start by disconnecting any door courtesy light harnesses (if you have them), then tracing the blue/black wires from the courtesy lights themselves to see if there was an obvious splice to the power lines.
 
^^^^Freaking GURU!!!

Lives 90 miles from me and I've never met him, what's my damn problem? I go to Southport about once every 2-3 months.

Allen
 
Since this is a NEW problem (constant "on" of the courtesy lights) in a car he's owned for a while I think it fair to rule out a PO wiring mess. At least as the cause of the courtesy light issue. It also seems that the logical problem is a faulty door switch. It is about as easy as it comes in terms of testing to verify if a switch is bad. Start there before getting carried away.
It's possible there is more going on and the lights and the gauge issue are somehow related but trust me, as an old field tech, it's usually something simple and obvious. It's also usually related to something someone JUST DID prior that they never tell you about or simply do not correlate so do not consider.
 
Thanks for the suggestions. I will check them out today.
I do have a multi meter and will check the switches for continuity.
The harnesses are original and nothing has been spliced into them.
The only extra wires in the car are the ones I ran to a block on the firewall to supply keyed power to the choke on the carb and one
to a modern radio in the glove box. I connected a wire to the starter solenoid, then to a junction block and then one to the carb and one
to the radio. That was 15 years ago. Nothing has been done since but routine maintenance.

Here is a pic of the cluster connections. I am assuming that the courtesy lights have nothing to do with the CVR and when they get sorted out
I'll need to deal with this next.
Cluster.jpg.
 
CVR has nothing to do with courtesy lights.

When you tested the door jamb pins, were both door jamb switches removed? Was that the condition when both pins were hot?
When testing door jamb pins (wires), both door jamb switches must be inoperable and the headlight switch not in courtesy light mode.
 
LNimoy said:
With the headlight switch removed, I popped out the two door jamb switches.
With the key in the off position, I have power to all four wires of the jamb switches, two on each side, and to the wire that goes to the glove box light.
Click to expand...
Just to be certain here- the headlight switch is unplugged, and the two door switches are not connected- is that right? When you check for power is one meter lead going to a door jamb wire (the switches are removed) and the other meter lead is going to chassis? If that's the case and you still have 12v, then you have a short and somewhere a power wire is connected to the light side of the circuit. I would pull fuses out one at a time to try and find where the power is coming from. Once you know that you will have to follow that circuit throughout the car to find the short. Or conversely follow the wires that connect to the lights back to the door jamb and light switches looking for a short. You'll need a wire diagram and lots of patience for this type of problem. Keep us appraised of the results and maybe we can help. By the way, I'm a Spock fan and am curious, what does the L stand for in LNimoy?
 
I think that I have multiple issues which are confusing me. When I took the car out, everything was fine, gauges courtesy lights etc.
I noticed the courtesy lights the next day. When I started the car to check the battery is when I noticed the gauges and when the car wouldn't shut off even with the key removed. I went to remove a battery terminal and heard a "humming" near the solenoid. Replaced the solenoid and car starts and shuts off fine. Humming noise gone. Replaced the ignition switch as a precaution to prevent the car from running with the key off.
When I tested the wires for the jamb switches, the headlight switch was removed, both jamb switches were removed and the glove box switch was removed. All four wires on the door switches were hot, (both wires on each jamb switch) which I thought was odd. The glove box wire was also hot with the switch removed.
The glove box switch fell apart when I was removing the passenger door switch and trying to get some slack from the harness under the dash to the jamb switches.
It's been raining here and I can't pull the car out to test the jamb switches for continuity. I put them back into the jambs.
I only mention the CVR as I'll have to deal with that after the courtesy light issue.
Thanks for all the suggestions, I really appreciate it. I'll test everything that anyone suggests.
 
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