I have a 1985 IROC with TPI that has been running perfectly until I took it out for a spin last week. Yesterday, went out to crank it and the battery was completely dead. Replaced the battery and then hooked up a multi meter to test for a battery drain. Found one that is very odd. It's not constant, but every 15 seconds the draw starts and is around 7amps. 3 seconds later it goes back to 0. 15 seconds later it does the same thing and continues without end. I can hear a muffled click on the passenger side near the firewall when the draw starts and then a slight "ping" when is shuts off 3 seconds later almost like a relay or solenoid. Any ideas what might be causing this before I start pulling fuses?

 

Well I started pulling fuses and it turns out it was the courtesy fuse....Now what on this circuit would come on for 3 seconds and turn off and then repeat about every 15 seconds? The car has no power windows, or door locks. Is there some relay or solenoid I'm not thinking about?

 

Power antenna?

 

Aftermarket Alarm System...

Although 7 Amps is a MASSIVE parasitic-draw!!!
The battery must die very, very quickly.

What do you have for aftermarket electrical components/ accessories installed?

 

Difficult to describe wiring troubleshooting in words; just pull 1 fuse at a time until you find the circuit in question, then trace it using the wiring diagram for your car in the FSM.

As mentioned above, 7 amps is a large draw, and should make it easier to track down.

 

No alarm or aftermarket hookups at all. The click and ping that I hear when the draw cuts on and off sounds like its coming from under the dash somewhere behind the radio. The radio is aftermarket, but is that on the courtesy fuse circuit? Also, it does have a power antenna but not sure if that's on the courtesy fuse either. And it does kill the battery quickly...

 

Both the radio and the antenna relay are on the courtesy fuse. The radio uses it to maintain the stations and clock.

The antenna relay uses it to power the antenna motor. It is the relay for the antenna up/down that is clicking. Note that this is an orange wire.

RBob.

 

Thanks! Going to try this today.

 

Thanks RBob and sofakingdom.....it was the power antenna relay. Appreciate all of your input.