I am at a loss trying to figure out my power draw issue. Any help is greatly appreciated. 1985 Z28, mostly stock 305 tpi, fan temp sensor went bad over 10 years ago so I rewired the fan relay to stay on with the ignition. Last week I took the car to work and everything was fine. Got home that night and the fan stayed running after turning the car off. No other accessories were on (radio). I figured the fan relay was bad so I just unplugged the relay. The next morning the battery was completely drained, couldn't even jump start it. Now I'm trying to figure out why the fan is staying on with the key off all of the sudden. The ignition wire to the relay is hot at all times now. I can pull the fan fuse but the battery still drains. I can't find any other fan relays for the 1985 system. Is it possible the ignition cylinder in the column is bad and only sending power through the fan system? Any other thoughts?

 

My thought is that you ended up using the ignition switch to switch the power to the fans , and that the mad amount of current the fan draws eventually welded the ignition switch contact closed , and that you need a new ignition switch . (after you put the fan wiring back to being proper so you don't fry your new switch which , BTW , is not behind the steering wheel or ignition key , it's part way down the steering column , sorta near where the steering column goes through the floor . In other words you will not be removing the steering wheel or ignition key lock cylinder to be replacing the welded closed switch) .

 

I did not know there is another switch further down the column, thanks for the idea. I bypassed the relay because I couldn't get the temp switch that had failed out of the block. I was much younger then so I'm going to try it again and see if I can get it fixed the right way. Probably lasted as long as it has because I only drive the car maybe 6000 miles a year.

 

Finally got a chance to change the switch but it didn't help. I did notice that with the switch unplugged, the fan is still running. Is there any way wires could be crossing in the loom somewhere? The radio and all other power accessories work as normal. I can pull the fan fuse to stop the fan but the battery still goes dead so the problem has to be before the fuseblock.
Thanks

 

A strange thing occurred while I was putting everything back together. The fan was running and then just stopped, and cycled on and off with the key. Then a few minutes later, it started running constantly again.
I also noticed that in the fuse block, the heater/ac fuse and the tail light fuse is hot with the fan fuse. Is there a common wire that feeds those three fuses?
Thanks for any help.

 

 

Thanks for the reply, I have narrowed the problem down to a bad voltage regulator in the alternator. I was looking at wires and tracing where they went and fan would turn off and on again. Started moving different wires to see if the fan turned off. Followed a wire from the battery to the alt and saw a brown wire from the alt to the starter switch. If I unplugged the two wire plug on the alternator the fan would quit. So I got a new voltage regulator installed and now waiting on the battery to charge. Will update when the battery is charged and I can test it.

 

ace16a, curious to see if you fixed the problem. Any update?

 

The alternator was the problem. Replaced alternator and everything works as it should again.