Cooling fans stopped working

kevins2 · #1 (**permalink**) 11-02-2013, 02:24 PM

Well, my first start went well and everything worked initially - I'll update my thread when I get a chance. Then, the cooling fans stopped working. I have the two front fans and the puller fan. What I've done so far:

Swapped the horn and fan relays, checked the connections to the dash override switch and touched the two leads on the thermoswitch together to see if the switch was bad.

All the fuses look good.

Any ideas?

Thanks,

Kevin

Tim Brewer · #2 (**permalink**) 11-02-2013, 03:22 PM

First thing I'd do is get an outside 12v source to see if the fans work like that, and then work backwards to your switch. But you know, they really don't do anything anyway and they'll turn while you drive with no powerhooked up at all.

patrickt · #3 (**permalink**) 11-02-2013, 03:29 PM

Quote:

Originally Posted by kevins2

Well, my first start went well and everything worked initially - I'll update my thread when I get a chance. Then, the cooling fans stopped working. I have the two front fans and the puller fan. What I've done so far:

Swapped the horn and fan relays, checked the connections to the dash override switch and touched the two leads on the thermoswitch together to see if the switch was bad.

All the fuses look good.

Any ideas?

Thanks,

Kevin

I would then suspect the plug that is on the driver's side, adjacent to the radiator, right at the fender well. Turn your fan override switch on and start wiggling that plug and the wires to it. See if that fires her up....

kevins2 · #4 (**permalink**) 11-02-2013, 04:28 PM

Hi Tim,

I agree that the front fans are just decor, but the puller fan certainly isn't. Fortunately, I noticed the temp creeping up and shut it down before it completely overheated.

Patrick, checked that plug (#44) and measured the voltage coming from it with the override switch on - nothing there. I assume if the override switch went bad, that wouldn't cause the auto part of the circuit to stop working.

Any other ideas?

Thanks,

Kevin

patrickt · #5 (**permalink**) 11-02-2013, 04:33 PM

Quote:

Originally Posted by kevins2

Any other ideas?

The thermo switch in the hose and the override switch on the dash both just provide a ground path to the relay on the firewall. The fact that you do not have 12v at the plug by the radiator means the problem is "up stream." Pull the relay out of the socket, turn the override switch on, and see if you have 12v there at the socket. There are only so many things it can be -- this is not hard.

patrickt · #6 (**permalink**) 11-02-2013, 05:19 PM

After you find the gremlin that's keeping your fans from coming on, the next step will be to do this: Cool Modification - For Pusher Fans Only, Though Really, I think ERA should wire them initially this way.

kevins2 · #7 (**permalink**) 11-02-2013, 05:22 PM

Hi Patrick,

You're right - there aren't that many places for a problem to hide, so it shouldn't be that hard. I was out there checking voltage at the relay when you posted this. Nothing there so went back to the fuses. Learned something about these glass fuses. The fuse looks perfect, even when I took it out and used a flashlight to look inside at each end. But, no continuity - can't trust a visual inspection. Put a new fuse in and that was it.

Thanks for the help. Much appreciated.

Regards,

Kevin

patrickt · #8 (**permalink**) 11-02-2013, 05:26 PM

Quote:

Originally Posted by kevins2

Put a new fuse in and that was it.

It's going to blow again -- the fans pull more than you think. At a minimum, up the amperage of the fuse, but you should probably split the circuit with dual fuses as I did in the cool modification referenced above.

kevins2 · #9 (**permalink**) 11-02-2013, 05:28 PM

Now, the bigger question is why it blew the fuse...

Guess I'll just have to drive around some more tomorrow to see if it happens again

kevins2 · #10 (**permalink**) 11-02-2013, 05:32 PM

Our posts crossed in the ether. It is a 30 amp fuse - that's a lot. I'll get a couple of spares short term and see how this plays out. Looked at your mod. Good idea to have redundancy, but I think I want to get my car on the road before I start changing things on it. Don't want to void the warranty

patrickt · #11 (**permalink**) 11-02-2013, 05:36 PM

Quote:

Originally Posted by kevins2

Our posts crossed in the ether. It is a 30 amp fuse - that's a lot. I'll get a couple of spares short term and see how this plays out. Looked at your mod. Good idea to have redundancy, but I think I want to get my car on the road before I start changing things on it. Don't want to void the warranty

The current draw on your fan circuit is not static. The current will vary with the underhood temperature and with the voltage in the circuit. The fans will draw significantly more current when your engine is hot and you are idling (and your voltage is lower than when your revs are up). Those pushers will pull just under ten amps, and your puller can easily pull close to twenty. Add in some heat, some voltage drop at idle, and *poof* goes the fuse.

kevins2 · #12 (**permalink**) 11-02-2013, 05:46 PM

That's exactly the scenario. I had just come back from a drive around the neighborhood area (I'm not legal yet, so trying not to push my luck too far) and was idling in the driveway looking things over for leaks or any other sign of trouble. Got back in the car and noticed the temp had climbed up. So, the fuse probably blew while it was sitting there idling. Couldn't hear that the fans had stopped...

patrickt · #13 (**permalink**) 11-02-2013, 05:54 PM

Quote:

Originally Posted by kevins2

That's exactly the scenario. I had just come back from a drive around the neighborhood area (I'm not legal yet, so trying not to push my luck too far) and was idling in the driveway looking things over for leaks or any other sign of trouble. Got back in the car and noticed the temp had climbed up. So, the fuse probably blew while it was sitting there idling. Couldn't hear that the fans had stopped...

Run the fans, with the engine off, for a few minutes there in the garage to see if it blows again... it probably won't. Also, the "surge current" when all three fans come on at the same time is pretty darn high. Those are "slow blow" fuses, too.

kevins2 · #14 (**permalink**) 11-02-2013, 06:08 PM

Good idea to test. At least I know what's going on so can move on to other things.

Thanks again for the help.

Kevin

patrickt · #15 (**permalink**) 11-02-2013, 06:10 PM

Of course you know that if you take her out, get stuck in traffic, and blow that one single fuse, and start overheating, then you're in for a really, really shiitty day.

kevins2 · #16 (**permalink**) 11-02-2013, 06:15 PM

Yep, will talk with ERA about a better long-term solution than carrying spare fuses. Short term - there's no traffic on the back roads around my neighborhood. More likely a ****ty day would be a cop in my rear view mirror...

DanEC · #17 (**permalink**) 11-03-2013, 02:58 AM

Kevin - not to hi-jack - but did your alternator seem to be charging normally on your test drive?

Dan

kevins2 · #18 (**permalink**) 11-03-2013, 05:38 AM

Hi Dan,

Nothing to hijack here, the problem is solved. Never saw a perfect looking blown fuse like that, so lesson learned. Guess we should carry volt meters as part of our tool kit

Yes, the alternator seems to be charging just fine. The red light goes out immediately when I start the engine and the ammeter indicates charging.

Regards,

Kevin

DanEC · #19 (**permalink**) 11-03-2013, 06:24 AM

Thanks - That's one fortunate thing. I've got to work on that charging issue again sometime.

Dan

kevins2 · #20 (**permalink**) 11-03-2013, 06:32 AM

Hi Dan,

Hope you find that problem. I assume you've started from the beginning and checked all the connections. Hopefully it something easily corrected.

Regards,

Kevin