jdhh74

iTrader: (2)

Hi,

I could use some help/advice with an issue that just popped up.

I have an '84 L69, 5 speed manual Trans Am. When I got the car home yesterday afternoon and turned the engine off there was a loud buzzing from inside the car (with the engine completely off, key out of ignition). The buzzing would stop if I turned the key back to the accessory position or turned the engine on. It sounded like the sound was coming from the convenience center and, if I pulled the choke heater fuse, the sound stopped. My first thought was a bad choke heater relay, although I was surprised it was making noise when the car was off.

I didn't have time to explore the issue more yesterday (New Year's Eve plans) and went back to it this morning. I put the choke heater fuse back in and went to start the car but found it was totally dead. The battery seems to have drained overnight.

Any ideas what may be going on? I've seen some posts where a buzzing from the CH relay was solved by just replacing the relay, others where it indicated an alternator issue. The alt could be bad, but why would the battery drain overnight when the car was off? Could the Choke have been draining the battery somehow? Even with the fuse pulled?

If anyone has any suggestions of what may be going on I'd appreciate them!

Thanks,

John

sofakingdom

iTrader: (1)

Sounds like an alternator problem.

One of the diodes in the diode trio has failed, shorted.

This type af failure allows current to flow when/where it shouldn't. In this case, it flows at all times from the batt, through the field windings, to ground. That's what is draining the batt.

Verify by disconnecting the alt (the big wire and the little plug). Buzzing should stop and batt should stay charged.

tyranero

Incredible timing, seems like I have the same issue.

Background: I have a 84 trans am, LG4 (H) and I also have the buzzing, along with high idle when the engine is hot (both high and low).
I had the alt recently bench checked when my battery died, but it passed all checks, the battery however was indeed bad, so I replaced it. Soon after (around xmas), the heater relay started beeping and I smelt something burned, turned out to be the C/H fuse.

I replaced the fuse, idle went up, Choke light came on (didn't even know I had one, was never on before), few hours later the fuse blew again, idle went down to normal. New fuse in, idle went up again, go figure...

When I pop the hood and look at the carb itself, the choke is about half way open and it's pretty lose, nothing changes when I open it manually to full. If I press the throttle all the way closed (against the body) the rpm go down to about 900 (which is still too high), but the little screw next to it is already at full extend.

Figured I'll start cleaning it inside and out with some carb cleaner (while it's in the car) and see if something is just a bit sticky, but since the relay blew at the same time I figured something more is broken...

jdhh74

iTrader: (2)

Hey Sofakingdom,

Looks like you were right. I put a new battery in and got the same problem - the car is off, key out of ignition but there is a loud buzzing noise from Choke Heater Relay. When I unplug the generator the buzzing stops.

So - I'm assuming the generator needs to be replaced? PITA.

Thanks,

John

five7kid

iTrader: (14)

Alternator isn't that much harder to replace than the battery.

tyranero

Btw, turned out my choke heater coil had a short. Pulled the choke off the carb to fix my rpm issue (in Cali it's not really needed anyway) and measured everything, the coil has bad resistance. You can measure it from the outside between the terminal (that 1 wire connector) and the housing of the heater, if below 10 ohm it's probably bad.

Oh, and the relay stopped buzzing.