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The past few months when driving my 1984, the power would occasionally go out. Usually, it was just the radio. Other times, it was the radio and the cluster. The car itself never seemed to notice, the engine kept running just fine. At first I though it would only happen when I hit a bump, but recently it's been happening even on smooth roads while driving straight. Yesterday, I turned the key to ACC, rolled down the windows, tuned the radio, got ready to start the car when the power went out. Everything was off. This time, I got out, unplugged the battery and that appeared to fix it. I drove it a couple more times yesterday with no issue.
This morning, same thing. Had power for a few moments, then it goes out. Unplugging the battery didn't help. I had to get to work, so I didn't spend too much time on it, but I did measure the battery and got 12.8 V. I left it disconnected for now because I've had issues with drain in the past.
Where do I begin? I do have the FSM (at home) so I'll look through the electrical diagrams there later. Do I just start measuring Volts until I can find what got shorted? Or is there a place where the radio/cluster/starter all come together that I should look at first? I was considering the ignition, if only because it switches all three of those rails.
The past few months when driving my 1984, the power would occasionally go out. Usually, it was just the radio. Other times, it was the radio and the cluster. The car itself never seemed to notice, the engine kept running just fine. At first I though it would only happen when I hit a bump, but recently it's been happening even on smooth roads while driving straight. Yesterday, I turned the key to ACC, rolled down the windows, tuned the radio, got ready to start the car when the power went out. Everything was off. This time, I got out, unplugged the battery and that appeared to fix it. I drove it a couple more times yesterday with no issue.
This morning, same thing. Had power for a few moments, then it goes out. Unplugging the battery didn't help. I had to get to work, so I didn't spend too much time on it, but I did measure the battery and got 12.8 V. I left it disconnected for now because I've had issues with drain in the past.
Where do I begin? I do have the FSM (at home) so I'll look through the electrical diagrams there later. Do I just start measuring Volts until I can find what got shorted? Or is there a place where the radio/cluster/starter all come together that I should look at first? I was considering the ignition, if only because it switches all three of those rails.
Sounds like a grounding issue. Check in your manual for the locations of the grounds and go around and check them.There is a ground to the under the left dash area under the carpet to the left that goes to a lot of dash.
Also are you sure you are loosing voltage not just an instrument cluster? They can be flaky too. See the guy and all his videos on repair of the cluster or you can contact his website to get it repaired:
I have checked out Batee before, and at some point will probably buy the bulb kit from them.
I'm pretty sure it's not just the cluster due to the radio, windows, headlights and hatch not functioning. Though there could be a short in the cluster. I haven't had that out yet.
I'll certainly look at the grounds, especially the ones in the dash vicinity.
Last edited by ValourUnbound; 09-28-2018 at 05:23 PM.
There is a ground on the driver's side right next to the oil filter. On my '84, it was real loose. When I tightened it up, my flickering dash issues went away. Not sure about the other electrical issues, but worth looking into.
Good Afternoon,
I would go to the basics first. check the fusible links then the circuit breakers, and starter connections.
Leave the radio on and start wiggling stuff in these locations.
This will only take a few minutes and diagnosing bad grounds could take hours......... and hours.
Just a thought....
Small update:
I started looking into the grounds until I realized that I'd have to take half the engine apart, or go in from the bottom. I may look into that later.
After I got the last post, I turned the key and started wiggling fuses and such. I futzed a bit with the radio, since it pulls right out in my car and with the cables behind it.
When I got out of the car, I saw red. My brake lights were on. Not quite sure how that happened, but it makes me want to look further into the radio/cluster mess. At that point I started smelling burning, so I unplugged the battery.
I suppose that is technically worse, but I'll call it progress.
Last edited by ValourUnbound; 02-28-2019 at 09:00 PM.
I suppose this might be necro, but it is my thread so....
I haven't had a lot of time to work on the car due to school/work. Yesterday I was able to look at it for a couple hours. I think the correct way to describe what happened is: 1 step forward, 2 steps back.
The short version is: Everything to do with the brake lights being on, the fuse being hot, etc was from the brake light switch under the brake pedal. It had fallen out. One day I'll rig it so it can't fall out, but it seems to stick well enough for normal use. I was able to start the car with no issues, all the lights worked as expected. As soon as I lowered the car off of the jack stands, the power was gone again.
So, I guess I'll jack it up again and do what I intended to do when I jacked it up two months ago: check the three fusible links that are attached to and around the starter. Also, look for any grounds that may be accessible from under the car.
Well, this problem is still bugging me, but it took a break. Note that for the above post, the brake lights being always on was caused by the brake switch falling out of it's hole. I stuck it back in and everything was good.
From 1/5 through 2/20 the car had no problems. It would start up when I asked it to, except for once at the gas station when it needed some patience.
On 2/21 it gave up and needed to be towed home.
Since then I've gotten some good debug info. And a creeper, which helped me get that debug info
The state as of now is as follows:
Hot to ground on the battery is 12V
Hot to ground on the headlight motor circuit (easiest plug to access) is 1.x V. That's bad.
Went under the car to look at the starter, as I didn't have the problem before I replaced it. Found that the housing was shorted to hot. Housing is supposed to be ground, so hot was shorted to ground.
Took the starter out. The always hot terminal did not appear to be shorted to ground, though the ignition terminal is. Not sure what the deal is there, but I'll come back to that later.
There are two cables that connect to the always hot terminal on the starter. One is from the battery and the other goes to the rest of the car (afaik). The battery side is not shorted to ground, but the rest of car cable is.
So, I took out all of the fuses and started checking each terminal. Note that I already checked all the fuses and none were broken. I found that three fuses had terminals that were shorted to ground: INST LMP, STOP/HAZ and GAUGES. That means I have potential problems with the cluster backlight, the PRNDL light, the turn signal indicators, the brake lights, the brake switch, the hazard light blinker, and whatever the Gauge fuse controls (a bunch of stuff). No problem!
I will next go through and see if I can find some midpoint connectors on each circuit and check for shorts. Is there anything that those three fuses have in common? It appears that they all have connections dealing with the cluster, so that could be a central failure point.
Went under the car to look at the starter, as I didn't have the problem before I replaced it. Found that the housing was shorted to hot. Housing is supposed to be ground, so hot was shorted to ground.
There are two cables that connect to the always hot terminal on the starter. One is from the battery and the other goes to the rest of the car. The battery side is not shorted to ground, but the rest of car cable is.
I think we have a problem with your terminology. If your starter housing was shorted to hot (12 v.), your battery would explode!
This same issue exists in your previous tests. RHarker and HonorDebt are probably on the right track, since no fuses have blown and nothing has exploded! When several things quit, but there's no smoke, you need to find what's common with those devices. A "short" circuit will result in a massive current flow. A bad connection will result in NO current flow. BIG difference!
I think what you're calling a "short" is the normal resistance you will see when a device is connected to the circuit under test.
By "shorted to hot" I mean that I had one end of my multimeter, set to continuity mode (aka beepy mode), connected to hot and the other end touching the starter housing and heard beeping. However, continuity mode won't tell me if it's momentary short or a permanent one. So yes, it is most likely a wiring issue as a real short would have much worse consequences than a loss of power.
On the one hand, I want to tape or somehow attach the two hot wires, without the starter, and see if I have power again. On the other hand, if there IS a real short, I really don't want to do that. I like my house.
Aaaand I just looked at continuity mode's instructions. < 200 ohms will cause the beep if my meter is set at the default. I guess I'll check that and then test again.
As a general rule, any time you are checking resistance (ohms scale or "beeper"), your battery should be disconnected. This will reduce your chances for destroying your multimeter.
It was indeed a fusible link. The one that goes from the starter to two wires (the other two links only go to one wire). I'm not sure if it was actually burned through or if was from age/environmental factors, but it was certainly in trouble.
Note that I did replace the fusible link all the way from the ring terminal past the splice (? the black round thing). The way the FSM says to do it.
After replacing that, I have power! I'll have to give it a drive when it stops raining and see if I broke anything while I was fixing things.
Also, I did have the battery disconnected while measuring ohms. I don't get anywhere near the starter with that plugged in. I like living It is a bit strange to read 0.5 ohms hot to ground though. Once I plugged the battery in (I had paramedics on pre-pre-alert), it went back up to infinite (open).
Thanks for the help everyone!
09-28-2018, 01:04 PM
1984 No Power
