moon9398

New Member
Sep 29, 2018
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1
new mexico
ok I have a 93 mustang with electric fan, pretty new 180 thermostat and 3 bar mishimoto radiator. My heater will sometimes randomly come on after leaving it on and driving 30 plus minutes. But never reliable and it's getting colder so it's a priority. Rear defrost works great tho. My AC doesn't work either I think it may be the AC switch on passenger side engine wall cause the compressor doesn't kick on. Any help would be great. Im completely dumb in the terms of HVAC.
 
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When you say the heater randomly comes on, do you mean the fan comes on and off, or do you mean the air that comes out gets cold and then warm again?
 
When you say the heater randomly comes on, do you mean the fan comes on and off, or do you mean the air that comes out gets cold and then warm again?
So basically I'll turn it on full heat and it blows like it's on low but it's on high and while leaving it on for a while it will sometimes go from either cold to Luke warm air to hot but still doesn't blow hard enough to really get warm
 
#1 does the fan just blow on one speed?
#2 are you stating that the temp fluctuates?
just trying to understand if you one or two problems

1. No I can tell different fan speeds on low and on high but low is almost non existent and high feels like normal low

2. The temp doesn't fluctuate per se.
It's like it randomly kicks on and let's heat out not for long and with the blow speed being so bad it doesn't make a difference
 
Appears to me you may have two problems. The first thing I would do is fix the fan speed problem, check for power at the blower motor, with the switch on high, then run a jump wire (12 volts) to the blower, it should blow fast, see where your air is coming out at,
 
Sounds like you need a blower motor resistor... or the plug at the fan is loose or making a bad connection.
 
Here's the heater wiring diagram for your 92 Mustang.

Pigtail repair kits are available at most auto parts stores for damaged connectors. The hard part will be getting the parts counter person to look them up correctly.

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