Any Known issues that would drain the battery on a 86GT ? , I parked it for a week like always and came back to a dead battery. I thought the battery shorted out but it checked out Ok..
And for any '84 to '86 Fiero, headlight motors are a prime suspect.
Thanks so much, that would be the little blue box ( chime) under the dash on passenger side ?
I'm charging the battery now, once charged I'll keep an eye on voltage and see if it drops over the next two weeks as I will not be driving the car. Its been fine so far except once when I was doing a lot of work on it and had the doors and trunk open, assumed thats why the battery drained down, maybe it was something else.
Besides the radio clock are there any other parasitic loads in the car?
[This message has been edited by hunter29 (edited 07-12-2020).]
If it's the headlight motor, while it's charging, place your hand on top of the motor. If it's warm or hot, that's the problem. Unplug the single wire lead from the motor. Generation 1 motors have been known to start fires.
I had a friend whose Fiero battery kept draining. Took it back and they said there was nothing wrong, but it kept draining. Turned out to be the overhead light or footwell lights, I forget which. He had turned it on with the adjustable dimmer on the light switch. He just never noticed it because he had the door open when trying to start it.
The oil pressure sender can short but you would probably hear the fuel pump running if it did. It has full time 12 volt going to it.
[This message has been edited by fierofool (edited 07-12-2020).]
If it's the headlight motor, while it's charging, place your hand on top of the motor. If it's warm or hot, that's the problem. Unplug the single wire lead from the motor. Generation 1 motors have been known to start fires.
I had a friend whose Fiero battery kept draining. Took it back and they said there was nothing wrong, but it kept draining. Turned out to be the overhead light or footwell lights, I forget which. He had turned it on with the adjustable dimmer on the light switch. He just never noticed it because he had the door open when trying to start it.
The oil pressure sender can short but you would probably hear the fuel pump running if it did. It has full time 12 volt going to it.
Thanks for that also, looks like I may have some trouble shooting to do, only other thing I can think of is I left the trunk open but closed thinking I was going back in there but I have no memory of doing that.
Funny, all these years here, and i don't recall ever being aware that the blue dingy thingy could be a battery drain... although in my own defense, none of my Fieros retained that nuisance device after I bought them.
I want to second the headlight motors; One of mine started running after I had shut it off (Makes sense).....But two days later the other motor started running even tho I had not run it in those two days......Just started trying to lower the (Already lowered) headlight....the motor heated up to 160 degrees before I could disconnect it....
I had suffered two dead battery incidents in the year before.......
Thoughts; I would fully understand if the HL motors failed to shut off after I had lowered the HLs.......But it was surprising to me that the one motor just started on it's own 2 days after I had used it. The internal limit switches (Inside the motors) were actually very dependable......For THIRTY years...But we are now closer to 35 years (Average) so they are starting to become...undependable. To reiterate, they can start all on their own without having been run recently!
I switched my 1985 Fiero to the later 87-88 system.......I recommend this change but also added a relay in the main motor power wire so that the motors only get power when the KEY is on....That mod should be done to all 84-86 Fieros so they can't catch fire (At least from HL motors) Here is the link.
For the most part the limiter switches are still very dependable unless the brushes wear out and pop off. If the motor is able to build enough torque, it will break the pointsets that turn off the power. If they don't turn off the power, the thermal switch on the limiter switch assembly takes over, intermittently turning the power to the motor off and on. Mind you, that the motor has power going to it full time and the limiter switch pointsets actually act as on and off switches. One set is open and the other is closed, depending upon whether the lights are up or down. The interior light switch switches power to the closed set to move the headlight in the opposite position from where it might be.
When the thermal switch is switching off and on, the motor will twitch or you may hear an audible click. If the motor is running, there are two things that will cause that. Either the plastic gear has had some of it's teeth stripped off, or the plate that transfers motion from the motor to the gear has come loose from the shaft. If the motor has never been opened, the likely cause is that the gear is stripped. If the motor has been rebuilt at any time and the drive plate was not properly installed on the shaft, it can come off, therefore losing its ability to receive rotation from the gear.
Then, there's the fact there are some inferior quality plastic gears out there. I just rebuilt a motor that very recently was rebuilt by the owner. The teeth were stripped off the gear.
The gears are undersize, and the teeth are concave instead of being level. When placing them on a flat surface and viewing them on the level of the surface you can see that they are only sitting on the outer edges of the teeth. That is the only area making contact with the gear that drives them. Add to that that the diameter of the gear is too small leaves only about a fourth of the outer ends of the teeth to take the load of the headlight mechanism and the headlight door springs. It's destined for failure.
So, if you're replacing your gears with plastic gears, compare diameters and check to be sure the full length of the teeth touch a flat surface when the gear is stood on the teeth.
Ok, found it, driver side headlight motor, maybe, I can hear the relay cycle about every two seconds, click click... what would cause the relay do do that? where should I start looking ?
When the thermal switch is switching off and on, the motor will twitch or you may hear an audible click. If the motor is running, there are two things that will cause that. Either the plastic gear has had some of it's teeth stripped off, or the plate that transfers motion from the motor to the gear has come loose from the shaft. If the motor has never been opened, the likely cause is that the gear is stripped. If the motor has been rebuilt at any time and the drive plate was not properly installed on the shaft, it can come off, therefore losing its ability to receive rotation from the gear
This may be the case , The motor did twitch, so replace or rebuild..
It can be rebuilt. It may be that one of the brushes has popped off. In that case, it would require a repacement limiter switch.
The motor isn't building enough torque to open the points and turn off the power. It could also be that the bump stops inside the gear have deteriorated, or inferior bumpstops were installed during a prior rebuild.
Until the issue is resolved, unplug the single wire to the motor. You can unplug it and leave the headlight up or down, but be sure the switch is in a corresponding position to the light when you plug it in. Switch off, light down. Switch on, light up. Then reconnect the plug.
I rebuild if you need. I suggest you order Rodney's metal gear. You can have him ship it direct to me and you can ship the motor. $30 labor plus return shipping via your choice of carriers. 1 year warranty on labor.
Gen1 HL motors are known problems here and seem 1 is bad now... Other motor is likely "bad" too but not "twitching" right now or slow twitching so won't kill the battery overnight or few days.
See my Cave, Battery Leaches for other problems to double check they don't cause headache too. Unplug Both HL motors to check other issues.
Note that you may need a new battery now or soon... Anything killing a battery several times can damage the battery shorten the life big time. At least is in summer... Low battery in winter can freeze and freezing ruin it fast.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
If you want a motor to rebuild on your own, I have motors. They were pulled from cars and haven't been verified or opened up to see the condition of the gear. I usually don't buy motors from a junk yard car if the headlights are raised. I assume that if they are down, they work. When they fail, most raise them and leave them up.
Stereos seem to go bad somehow and cause a drain...usually when the display dies.... I've had both stock and the newer generation Fbody 93-02 stereos do it...
