89er Posted August 23, 2011 Share Posted August 23, 2011 ac clutch and aux fan are not working. Tested fan and it is good, there is a lot of wires and relays that seem to be connected in the system so my best guess is a relay or switch has failed. Anyone had both fail at the same time? I am hoping this is a common failure and I don't have to do a complete inspection of all the components as its been 100 degree here and I don't have a shop to work in. :help: Link to comment Share on other sites More sharing options...
Truckcom Posted August 23, 2011 Share Posted August 23, 2011 I had a similar problem for years. The electric fan worked fine with the AC but, as it turned out, not with the thermostat. I finally got tired of the truck overheating when it sat at idle for extended periods and replaced the thermostatic fan clutch, thinking it was bad, with a straight non thermal viscous drive. This, of course, did not resolve the problem. It turns out the problem was due only to the fact that the male terminals on the relay were corroded. I would like to know if I should replace the fan drive with a new thermo drive. Like an idiot, I threw the old one away. I'm also curious to know how much power is wasted spinning a fan that's not needed. Any thoughts? Link to comment Share on other sites More sharing options...
ComancheKid45 Posted August 23, 2011 Share Posted August 23, 2011 so when you move the interior controls to A/C nothing kicks on correct? and the fan also does not kick on with the engine tempreture? Link to comment Share on other sites More sharing options...
89er Posted August 23, 2011 Author Share Posted August 23, 2011 Nothing clicks and no fan, I used a jumper to the battery and had power to fan so I know the fan is ok there are just so many dang connections that could be bad in the system and it does't help that PO liked to cut wires. It had been working fine now I have to watch temp guage when I'm stopped. Link to comment Share on other sites More sharing options...
87Warrior Posted August 23, 2011 Share Posted August 23, 2011 It could be low on freon. The ac system has a low freon switch that will keep the compessor from spinning as well as a whole host of other things. I would see about getting the system charged. Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 24, 2011 Share Posted August 24, 2011 It could be low on freon. The ac system has a low freon switch that will keep the compessor from spinning as well as a whole host of other things. I would see about getting the system charged. This is true for the HOs, but I'm not sure if it applies to Renix models also. :dunno: And the OP doesn't say what model he has. Link to comment Share on other sites More sharing options...
JeffN Posted August 24, 2011 Share Posted August 24, 2011 It's true for Renix also Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 24, 2011 Share Posted August 24, 2011 It's true for Renix also :thumbsup: Link to comment Share on other sites More sharing options...
89er Posted August 24, 2011 Author Share Posted August 24, 2011 oops sorry I have a 89 4L auto ac was rebuilt 6 months ago and converted and was really blowing cold when quit. No leaks all new lines. I don't have a wiring diagram for the ac/ aux fan system and there are a bunch of relays involved and of course the therm switch on the radiator. There are 2 wires that are not stock running to the batterry terminals and then to a relay on drivers side but I can't identify the relay and why they are there. I have a meter and will have to trace every wire if I can't identify the relays that are part of the system and the wire colors. I just love people who cut wires and bypass things, makes life interesting. The therm switch would't have a cut off for the ac if engine was overheating would it? Link to comment Share on other sites More sharing options...
JeffN Posted August 24, 2011 Share Posted August 24, 2011 find the low pressure cut out switch, it should be on one of the lines and take a wire and bridge the connection to see if everything comes on. It may just be a bad low pressure switch if the freon charge is correct. Link to comment Share on other sites More sharing options...
Eagle Posted August 24, 2011 Share Posted August 24, 2011 IIRC the aux fan is controlled by a standard relay that's attached to the inside of the driver's side fender, either between the air box and the inner fender or maybe just behind it. When I bought my '88 MJ the aux fan didn't work. When I finally got to checking that relay, the terminals were so badly corroded that they just snapped off. I had to cut off the old plug, solder on five standard spade terminals onto the wires, and connect them individually to a new relay. Link to comment Share on other sites More sharing options...
89er Posted August 24, 2011 Author Share Posted August 24, 2011 :cheers: I will try that and see thanks Eagle! I think the wires on the battery are bypassing the relay for the ac and I'm going to pick up a couple relays and replace them this weekend and will update. Link to comment Share on other sites More sharing options...
89er Posted August 24, 2011 Author Share Posted August 24, 2011 :banana: Well I have half sucess, replaced the ac relay and now have cold air and fan when ac is running, cleaned up a couple of wires PO added but still no fan when ac is off. The bases to the 2 relays on dr side look rough, I will try a new relay on them first and if that doesn't work I'll replace the bases like Eagle said. Link to comment Share on other sites More sharing options...
87Warrior Posted August 24, 2011 Share Posted August 24, 2011 The fan will only come on at the 230 degree mark with the AC off. You may want to consider wiring it to a manual on/off switch. Search the site and you will find out how to do it while retaining the relay functions. I ran my truck all summer with the fan turned on. Link to comment Share on other sites More sharing options...
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