Melted Fan Relay - pics

[Tim65GT]

On the way home Friday, I noticed a burning plastic smell for a second. When I pulled in the driveway and shut it off, the fan was still running. I poped the hood and removed my fan control cover and found:

Cheap plastic no name stuff. I shoulda known...

I replaced it with two Potter & Brumfeld relays. I also ran a 8 gage wire directly from the alternator and two 12 gage fuse links feeding each relay. I also soldered the wires directly to the relay tabs and did away with the connector plugs.

Other than that, my aluminum radiator/Taurus Fan swap has been working great. We are into the humid time of year with 100 degree days; the AC blows cold and the temp stays below190 even in traffic.

The 3G alternator is having a hard time now keeping the voltage up at idle. The draw of the Vintage Air AC Fan, the Taurus Fan and the 4 Extra #1157 bulbs in the sequential lights will drop the voltage to about 10 volts. If I'm at a long red light, I throw it in neutral and rev it to about 1200 to keep the volts up.

 

[rbohm]

a 130amp alternator having problems keeping up with the current draw, on a vintage mustang?????????????? sounds like you got other problems as well. you should have a 6 gauge wire at least from the alt to the battery, and a 2 gauge is best.

 

[Rusty67]

a 130amp alternator having problems keeping up with the current draw, on a vintage mustang?????????????? sounds like you got other problems as well. you should have a 6 gauge wire at least from the alt to the battery, and a 2 gauge is best.

I agree. These alternators put out more at idle then the 1g's did at full output. I notice you have a V-belt setup. Check the tension on the belts. A cheap fix could be to run a slightly smaller alternator pully but this might cook the alternator at high RPMs.

 

[Tim65GT]

a 130amp alternator having problems keeping up with the current draw, on a vintage mustang?????????????? sounds like you got other problems as well. you should have a 6 gauge wire at least from the alt to the battery, and a 2 gauge is best.

I have a 4 gauge wire from the alt to the bat

I agree. These alternators put out more at idle then the 1g's did at full output. I notice you have a V-belt setup. Check the tension on the belts. A cheap fix could be to run a slightly smaller alternator pully but this might cook the alternator at high RPMs.

I wouldn't even think about trying to run that fan on the old alternator.

The idle output of the 3G is supposed to be 60-80A at best. I think my demand equals or exceeds that. Since everything works great when I idle up a tad, my next fix will be to get the alt to spin faster. I want to go serpentine setup someday and a larger diameter crank pulley and small alt pulley I'm sure would give me enough oomph.

I'm also thinking of replacing the three 1157 bulbs in each taillight housing with LED's. That should save about 20-25 Amps right there.

 

[Rusty67]

A serpentine setup will be really cheap aside from the AC.

 

[mustangman1974]

I have had Bosch relays do that to. I stepped up to 70 amp relays found at a electronic store near my house and never had a problem since. (knocks on wood)