MilesFox Posted July 25, 2004 Share Posted July 25, 2004 the fan is on all the time. if you remove the brown relay the fan goes off. but the fan should only be on with the AC. if you turn the ac on, the blower will quit after a few minutes. if you remove the brown relay, it will blow colder. the ecu will flash codes although none of the test connetors are connected. is there a ground problem or what? the haynes schematic"typical 80-86 heating, ac, and cooling" is junk does anyone have a lead on a good schematic. i cant find any rigged up wiring of any sort. Link to comment Share on other sites More sharing options...
Cougar Posted July 26, 2004 Share Posted July 26, 2004 Check to see if the relay is shorted. If you have a test light, it would be good to see if something is causing the relay coil to be energized and close the relay, so see if there is voltage on the coil lead. I don't think the coil circuit requires a closer to ground to make it work, but it may. I have a manual for a '88 so I could check that. I assume the blower is ok in the heat mode, is that correct? If so, then the problem seems it would have to do with the AC circuit somehow but I would have to research that to see what could cause that. Link to comment Share on other sites More sharing options...
MilesFox Posted July 26, 2004 Author Share Posted July 26, 2004 no, the relay is good. i think this may have something to do with a short-to-ground in the ac circuit. this is jims 86 spfi sedan. the test connectors are under the dash. things i am keying on: codes flash with no test connectors connected, fan stays on without ac on. the thermoswitch fan cirgiot still works with the relay removed(jumper test) in the haynes book there is a "sub fan control" relay with a blu wire and a blu/black wir, and also 2 wires that go to "exterior lights" marked "nca" this is what i mean by haynes is junk. anyway, it shows the blu/black wire going to a "sub fan " relay, and blu/red then to "condensor fan" motor. but in between it has "nca" the blu/black wire goes to "condensor fuse". is this the one under the hood. if so the colors dont jive, there is a fat white and a smaller blue wire, and the haynes says blu/grn and wht on the sub fan relay the yel wire goes to the ac relay, and also to the main fan control relay. it shows te ac switch, low and high pressure switches in series, and the ac DOES come on, so those are obviously good if i unplug the ac(black) relay the ac turns off now whats screwy is i unplug the brown relay(which one is that?)and the ac blows colder, fan quits. but if plugged in, the ac is not as cold,and the blower will quit Link to comment Share on other sites More sharing options...
Cougar Posted July 26, 2004 Share Posted July 26, 2004 My manual is for a '88 model so I'm not sure how these systems will compare. Since you stated that pulling the relay will turn the fan off and you are sure that the relay is not shorted, then the problem is coming from the control circuit for the relay. Something is turning the relay on, when it shouldn't be. My manual shows a pressure in series with the coil of the fan relay and is tied to 12 volts on the other side of the switch. If this pressure switch was shorted it would cause the things you discribe. It would be worth checking that out. The blower problem sounds like there may be a bad connection somewhere and it is overheating while the fan runs. Then it will cause the blower to stop due to the high resistance. Link to comment Share on other sites More sharing options...
MilesFox Posted July 27, 2004 Author Share Posted July 27, 2004 i'll try pulling the wires to the pressure switches and see what that does. the blower fan will work normally on all other settings besides ac. Link to comment Share on other sites More sharing options...
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