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  • 1965 - 1973 Classic Mustangs -General/Talk-
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Fan Relay

  • Thread starter Thread starter Rapid
  • Start date Start date May 16, 2009
R

Rapid

New Member
Mar 31, 2005
297
1
0
Columbia, SC
May 16, 2009
#1
  • May 16, 2009
  • #1
I hane an Old Air shrouded electrical fan. One of the wires running to the fan motor gets hot enough that it has deformed the realy base and melted the plastic around the terminal on the relay.

This does not seem right.
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 16, 2009
#2
  • May 16, 2009
  • #2
Rapid said:
I hane an Old Air shrouded electrical fan. One of the wires running to the fan motor gets hot enough that it has deformed the realy base and melted the plastic around the terminal on the relay.

This does not seem right.
Click to expand...

It surely is not. This sort of thing is why I favor thermal-type clutch fans, no electrical system to screw up. Is the fan/relay cycling, or does it run all the time?
 
R

Rapid

New Member
Mar 31, 2005
297
1
0
Columbia, SC
May 16, 2009
#3
  • May 16, 2009
  • #3
it is working properly. It comes on at 180 and shuts backs off at 160. It does run most of the time these days.
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 16, 2009
#4
  • May 16, 2009
  • #4
Rapid said:
it is working properly. It comes on at 180 and shuts backs off at 160. It does run most of the time these days.
Click to expand...

Well, it's obviously drawing too much current. Did this wiring come with the fan?
 

iskwezm

10 Year Member
May 24, 2005
4,159
20
79
Rowland Heights,California
May 16, 2009
#5
  • May 16, 2009
  • #5
what size relay?What size wiring to the fan?
 
R

Rapid

New Member
Mar 31, 2005
297
1
0
Columbia, SC
May 17, 2009
#6
  • May 17, 2009
  • #6
Yes,

the wiring to the fan is the part that came with the fan. I changed the temperature sensor from a stick in the radiator to one that is is the thermostat housing and that is a painless unit. The original realy was a 30/40 amp. I replaced it with a 30.
 

Tim65GT

Active Member
Feb 24, 2004
1,149
2
39
West Texas
May 17, 2009
#7
  • May 17, 2009
  • #7
Some relays are better quality than others. For a 30 amp circuit, you should use 10 ga wire and 8 ga for 40 amps. Cheap, loose or incorrectly crimped connectors are also a source of resistance, which = more current = heat = melted components and wires. If all checks out, maybe the fan motor is going bad and is drawing too much current.

I melted a 30/40A relay, but it was controlling the high speed of a taurus fan. I fixed it with a 75A relay.
 
R

Rapid

New Member
Mar 31, 2005
297
1
0
Columbia, SC
May 17, 2009
#8
  • May 17, 2009
  • #8
Thanks,

I'll check connectorsd etc. I thing I have 10 gauge now.
 

BarnStang

Founding Member
Mar 2, 2001
1,260
3
39
Hagerstown, MD
May 17, 2009
#9
  • May 17, 2009
  • #9
I just caught this very problem on the Prostreet car on the headlights-no high beams after a front end rebuild. When I checked the dimmer switch it was so hot I nearly burned my fingers on it. One crimped connection was loose/high resistance. (Painless harness=no factory dimmer plug-done by PO) THis is a really good point Tim brought out cause sometimes you can't see this problem by looking at it visually without a very close inspection. Great picture of the melted relay!
 
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