Low Humming under hood when off : FIXED

[RedfordXLT]

I noticed last night after turning off the car there was the low humming noise coming from under the hood. I looked around but I couldn't really pin point the source of the sound. Well this morning I went to start her up and she was dead! I wasn't able to jump her either, but while the cables were connected the humming was present. I started pulling fuses from under the hood and the last large fuse before the standard fuses made the humming stop (see pic)

I don't know what this controls because like many others on this site I do not have the owners manual. I did find a site that would let you download them for free, but they only go back to 96!!

I don't know if this is related to my other post with the no brake lights or turn signals. I've tried almost everything suggested from reading other posts, but no luck!!


My previous post.....
I recently purchased a 91 XLT 4X4 5 speed. Everything was in proper working order until last night. I noticed my turn signals weren't working and I realized I had somehow popped out the flasher fuse while shifting. Well this afternoon the turn signals went out again and to my surprise the fuse was still installed. I had it tested at my local auto parts store and they said it has blown. So I replaced it and no luck. While checking the turn signal signals I noticed the brake lights are now also out. I read some of the other posts and I'll check the switch and any possible dirty connections, but what else could be the reason for the brake light to go out all of a sudden? My last question is how do you override or bypass the premium sound amps and where exactly are then? The kid at the custom audio shop where I bought wiring harness said it was in the back and easy to do, but nothing more than that! I don't have the owners manual or a chiltons manual for the car. I did look for a hayes / chilton while looking for my flasher fuse at the auto parts store and they don't have it for a 91. I thought perhaps the brake lights and turn signals had something to do with the fact that I swapped out the stock radio with an after market, but I've disconnected everything I did yesterday and they are still not working

Thanks

update.....
I just went and checked the brake switch and I manually made the connect between the two wires and the brake lights did not come on. I didn't check for any dirty connections because its dark and raining right now.

I also double checked all the fuses in the panel and under the hood.

What are the two or three other larger metal fuses in the panel? I know the round one is the flasher fuse, but the others? Again I don't have the manual for this car so any help would be appreciated.

I did however notice that there is a humming coming from the engine after everything is turned off. It almost sounds like a small fan or motor turning around constantly? You can hear inside the car and even in the back. I don't know if this was always present and never heard it or it is all in connection with what has happened over the past two days! I hope it doesn't drain the battery.....

I'll check more in the a.m.

 

[BP_93explorer]

I just checked my manual but it looks different. '93 Sport. Mine has two rows of fuses. 2 of my 30As go to the ABS, one is power locks and the other is EEC Power.

Maybe someone else here will have a manual for yours.

I just found that the lid (underside) to the fuses on mine have what they are. I'm sure you've looked at yours but just in case.

 

[pope_face]

I'm going to just throw out a guess, but I think that the fuse may be for the blower motor? Is there any air coming out of the vents with the car off? Maybe the wires shorted out and are running the motor at a low speed constantly... they may have caused the hum and the battery drain, and maybe when you start the car and attempt to turn on the blower it shorts out the circuit, blowing the fuse... but, I'm probably completely wrong. I'd check my manual, but I left it in the truck and I'm not too willing to trek across the yard in my skivvies through the rain to check... Just take a look under the fuse box cover, it should say... mine did.

Fil

 

[X6StringerX]

I just referred to my Haynes manual to see if I could help you out with fuse identification, but the manual has once again, proved to be useless. They show a diagram of the wiring, including the power distribution box (fuse box), but they don't identify the fuses. They even list the correct amperage, but not what they're for... how stupid is that?

 

[RedfordXLT]

I know...... I bought a Hayes book yesterday thinking it would help out, but it is proving to be useless and a waste of $20!

 

[savagefan]

I have a 91 automatic. According to the inside of the power box cover that 30a fuse is for the fuel pump relay which is in the rack below your fuses. Could be simply a bad relay or a mystery power feed causing the relay to buzz. I'd start with a relay (cheap and easy) good luck.

 

[RedfordXLT]

Humming Update

The humming from under the hood ended up being the fuel relay. I ended up taking it to a trusted mechanic and he said that explorers are notorious for this!

 

[savagefan]

Thanx for letting us know what it was.