1991 Subaru Legacy Radiator fans don't turn on when heater

SHOTLINE

MEMBER
1991 SUBARU LEGACY
4 CYL
AWD
MANUAL
170,000 MILES

I have an unusual problem. If I have any of the environmental controls on, AC, heater, vent, bilevel, defrost, etc, the radiator fans do not come on even when the engine is extremely hot. As soon as I turn the environmental controls to off the fans come on immediately and seem to go on and off as would be expected.

Another aspect of this is that when I turn on any of the environmental controls, the AC compressor engages.

Any ideas would be appreciated.

2 Replies

ABD141

MEMBER
6 POSTS

My car is a year older and had a similar problem, except it didn't kick on when the AC came on. It is possible the problem lies in the area of the thermostat/waterpump

If so, thermostat is an easy fix. Waterpump. Not so easy.

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Sunday, April 19th, 2009 AT 4:35 PM

SHOTLINE

MEMBER
2 POSTS

I thought possibly the thermostat as well so I changed it from a parts car I have and no difference. Also, since the fans operate normally when the environmental controls are off it shouldn't be the thermostat.

I have also changed out all the relays in the under hood fuse box for the AC, but no help. I am starting to wonder if it could be the mode actuator for the environmental controls as it interrelates to the AC and the cooling fans according to the wiring schematic.

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