Car won't run in Az...... - Page 4

Dangerous Doug · #1 (**permalink**) 09-08-2010, 07:09 PM

Next time you're out driving it, bring a DMM. When it dies, check the voltage at the coil. I'll bet you a beer the coil is internally shorted---these only fail when they get hot. If you have a horizontally mounted coil, I'll bet you a six-pack of ice-cold Spaten Optimator that it's the coil.

This has happened to me---twice---on two separate, non-Cobra vehicles.

DD

azfordman · #2 (**permalink**) 09-08-2010, 11:23 PM

Second night out and the fan is dead again!!! This time the brand new relay is blown out......... I know the car has some wiring issues, but this fan system is wired separate from the cars harness. I have power to the relay, and the switch wires gives me a good ground, but the relay is not sending juice to the fan. The only saving grace is I did not burn out the new fan......yet! So WTF am I doing wrong here???????

xlr8or · #3 (**permalink**) 09-08-2010, 11:38 PM

Go back and read that Taurus fan upgrade thread. You can get the fan brand new from www.rockauto.com for $90 and the wiring harness from www.thoroco.com for $60 and your cooling and fan issues will be resolved.

I did this on my coupe and it works great. I drove from Phoenix to San Diego last weekend during the hottest part of the day averaging 85 MPH with the A/C running and it was 114 degrees outside. The car ran a steady 205 and even less when i was stuck in line at the border patrol check points.

azfordman · #4 (**permalink**) 09-08-2010, 11:56 PM

Quote:

Originally Posted by xlr8or

Go back and read that Taurus fan upgrade thread. You can get the fan brand new from www.rockauto.com for $90 and the wiring harness from www.thoroco.com for $60 and your cooling and fan issues will be resolved.

The fan I got actually works pretty good as far as keeping the the motor cool, even at idle in the middle of the day in town temp stays below 90c. I would have no issue buying a wiring harness....if I had to....but it is just a relay and wires....not really rocket science.....sometimes when I get to close to a project I cannot see the obvious, I have to be doing something wrong because there is no reason to keep having these issues with something as simple as an electric fan.

Car Nut · #5 (**permalink**) 09-09-2010, 07:09 AM

Did the fuse blow or the relay?

Did you use at least a 12 ga wire for the fan power and ground?

Is your control circuit still hot?

Are you sure your ground(s) is good?

azfordman · #6 (**permalink**) 09-09-2010, 08:05 AM

Quote:

Originally Posted by Car Nut

Did the fuse blow or the relay?

Did you use at least a 12 ga wire for the fan power and ground?

Is your control circuit still hot?

Are you sure your ground(s) is good?

Fuse is fine
10 ga wire used
Not sure what you mean by control circuit....but, there is power from the + connection to the starter relay....hot at relay & power from the ignition switch +....hot at relay & ground is good at the relay from the switch. No power comes out of the relay to the fan when switch is flipped...... If I put 12v to the fan connection at the relay the fan comes on. Fan is good.

Relay is bad......

I am sure the answer cannot be buy a new relay every other day.......

patrickt · #7 (**permalink**) 09-09-2010, 08:12 AM

Did you solder all of your connections on the relay? A bad connection will increasee the current and can contribute to a burned up relay.

azfordman · #8 (**permalink**) 09-09-2010, 08:18 AM

Quote:

Originally Posted by patrickt

Did you solder all of your connections on the relay? A bad connection will increasee the current and can contribute to a burned up relay.

No...the relay has spade connections on it. If you tell me I have to solder the connections I will.....I am at a complete loss and I have no idea what else to do, but I find it had to believe that every production vehicle and every hot rod on the road with an electric fan has the spade connections on the relay soldered.....

patrickt · #9 (**permalink**) 09-09-2010, 11:08 AM

Quote:

Originally Posted by azfordman

No...the relay has spade connections on it. If you tell me I have to solder the connections I will.....I am at a complete loss and I have no idea what else to do, but I find it had to believe that every production vehicle and every hot rod on the road with an electric fan has the spade connections on the relay soldered.....

No, spade connections are just fine. It could be a long shot, but is it possible that the thermostatic switch is "jiggle-blinking?" You know, it's coming on and off in rapid succession like a loose wire will sometimes do? The way I would diagnose that obscure possibility is to have a 12v light wired in to the fan circuit and then positioned somewhere on the dash so I could see when the fans are coming on. If I saw the light blinking on and off that would tell me what was going wrong. Other than that, if your connections are good, your voltage is normal, your wire size is correct, your relay is properly sized, and you've gone through a couple to three fans, I can't guess what it could be.

Car Nut · #10 (**permalink**) 09-09-2010, 10:21 AM

Quote:

Originally Posted by azfordman

Fuse is fine
10 ga wire used
Not sure what you mean by control circuit....but, there is power from the + connection to the starter relay....hot at relay & power from the ignition switch +....hot at relay & ground is good at the relay from the switch. No power comes out of the relay to the fan when switch is flipped...... If I put 12v to the fan connection at the relay the fan comes on. Fan is good.

Relay is bad......

I am sure the answer cannot be buy a new relay every other day.......

I'm at loss, the only other thing I can think of is low voltage and Ohm's Law. If you have a lower voltage your amperage will go up. 40 amps at 12 volts will equate to 48 amps at 10 volts. However since it did not blow your 40 amp fuse, I suppose it can be you just happened to be lucky enough to get a bad relay.

Its also possible you could be getting a voltage spike in which case you may need to add a diode. http://www.the12volt.com/relays/relays.asp

Maybe the easiest thing would be to replace it and see if solves the problem

Maybe add the diode at the same time?

xlr8or · #11 (**permalink**) 09-09-2010, 10:06 AM

One of the concerns of with electric fans is the initial draw when they start up. Some will have a momentary draw of up to 60 amps.

vettestr · #12 (**permalink**) 09-09-2010, 10:12 AM

All good points in the last few posts. I hacked out a response and then lost it going to check another post. #$&(^_* Have you checked or measured what fan is really pulling not to mention the spikes? Gave up and sent you a PM