MilesFox Posted March 13, 2014 Share Posted March 13, 2014 The heater fan worked only one time in my 3door coupe, when i first got it. Even the turn flasher and wiper relay is slow to respond because the car had sat for a while when i got it. The resistor coils are intact, and the fan sitch did work. once had this problem in an 87 rx coupe back in the day. Where is this relay? i looked behind the glove box. All i found was what i believe is the pressure switch. I understand the schematic for this circuit. I have not done any voltage tests. I have had the dashboard out when i built it, but didn't think of the blower fan. Link to comment Share on other sites More sharing options...
Gloyale Posted March 13, 2014 Share Posted March 13, 2014 Group of 4 relays behind dash left of steering wheel. Blower relay will have a large, heavy gauge.....Green/White wire......Don't remember the connector color but it's the one of those 4 with the G/W wire. Link to comment Share on other sites More sharing options...
ruparts Posted March 13, 2014 Share Posted March 13, 2014 hi, i've had trouble with the fan in my rx also,, i have not found why it will randomly just go off , but it is not the relay, it seems to be the signal thet closes the relay. i've been unable to figure it out but i did wire a switch to close the relay and it seems to work fine just needed to power it from a switched source instead of the always hot i used,,, next time i can do better. it would work then while driving just turn off, some times woiuld not run in mornings,, later came on mysteriously, but the relay itself was not my trouble, yours might be but just saying.. Link to comment Share on other sites More sharing options...
MilesFox Posted March 13, 2014 Author Share Posted March 13, 2014 Point to consider. my rx back in the day was similar to your symptom. I just wanted to confirm the location before i start pulling interior pieces. Thanks Gloyale for the location. Your reference to a green and white wire triggers my mental image of the schematic. thanks Link to comment Share on other sites More sharing options...
robm Posted March 14, 2014 Share Posted March 14, 2014 These relays get flaky with age. They will work fine when tested, then stop working after being energized for a while (minutes, hours, etc.) It seems to be a temperature problem, so pulling it out and testing it on the bench to see if it is flaky won't work, as it is not in the same environment as it in place under the dash with the heater going. The coil stays energized, but the contacts don't make. Get one from the wrecker. Better yet, get the whole block of 4 from the wrecker. The next to go is the fuel pump relay, and that is a real pain. Link to comment Share on other sites More sharing options...
Gloyale Posted March 14, 2014 Share Posted March 14, 2014 hi, i've had trouble with the fan in my rx also,, i have not found why it will randomly just go off , but it is not the relay, it seems to be the signal thet closes the relay. i've been unable to figure it out but i did wire a switch to close the relay and it seems to work fine just needed to power it from a switched source instead of the always hot i used,,, next time i can do better. it would work then while driving just turn off, some times woiuld not run in mornings,, later came on mysteriously, but the relay itself was not my trouble, yours might be but just saying.. This would indicate a problem with the selector switch. Link to comment Share on other sites More sharing options...
ruparts Posted March 14, 2014 Share Posted March 14, 2014 These relays get flaky with age. They will work fine when tested, then stop working after being energized for a while (minutes, hours, etc.) It seems to be a temperature problem, so pulling it out and testing it on the bench to see if it is flaky won't work, as it is not in the same environment as it in place under the dash with the heater going. The coil stays energized, but the contacts don't make. Get one from the wrecker. Better yet, get the whole block of 4 from the wrecker. The next to go is the fuel pump relay, and that is a real pain. hi, thanks for that information, i had not thought to concider they might just disengage after working perfectly for hours over multiple days. anyway that thing about temp did seem to be a factor, on cold mornings sometimes the blower fan would not come on,, leav everything on and usually about the time i'd get to work suddenly it would come on. using the fan on a/c is the same if it came on it usually would stay on, but sometimes it would just turn off after running for an hour or more. the thing is , i got the 4 of them down and would try 4-5 maybe 6 other ones and none of them would kick it back on either, but test ok. i traced the wiring diagram in the fsm,, both the hitachi and the matsushuta (spelling) they are wired different within the system but the end is , the blower fan signal is tied in with some of the pressure switches in the a/c, and the temp micro switch on the heater case by the gas pedal area & tunnel, there is a diode inline on one of them. with blower on, if i trip that micro switch , it kills the fan,,, nothing will restart it till you cycle the ignition switch off then back on and it then allows the fan to come on again?? i know it sounds crazy, but in the fsm it mentions the need to reset something by doing that with the ignition switch. i think it was called a timer or time delay,, anyway i think it's built into the a/c amplifier module, which are different from each other , harnesses and all, on each of the 2 systems. anyway after many hours and much frustration, i just gave up and went to a toggle switch that closes the relay, BTW "same relay that had been in there all along", and has not turned off, not once , nor failed to come on, not once, so i firmly believe there is something else causing the trouble but i don't have the electrical background to fully understand the systems wiring interconnections and overrides completely.. i had another turbo 4dr f/t 5mt that had the exact same trouble, so it is a common issue on them but i still say it is a grimlin in there besides a old relay, which may well be so on some of them. but other relays (numerous different ones) has had no effect on my rx at all so i did what i could to get a fan that worked reliably and it has so far,, same old relay it always had. i made sure of that because i never thought it was the problem from the start, and i wanted to continue the experiment for later reference. thanks again, someday maybe somebody will finally figure out where this sneaky grimlin hides. Link to comment Share on other sites More sharing options...
ruparts Posted March 14, 2014 Share Posted March 14, 2014 This would indicate a problem with the selector switch. hi, thanks , i hear you there, i tore one up just to see how it works inside, internally the selector switch only has off or on,, off is off,, ALL other positions are on, i know the buttons have a/c, defrost, bla bla but they are all on a single buss bar inside.. i guess the contact could be intermittant (the contact on the one i dissambled was dirty and old grease, so contact could be compromised with temp or vibration) that said you may be correct, and onto the underlying intermittant part of this. now the more i think on it , the more it makes sense. that is 1 place all the different modes have in common with the blower fan relay signal. and my fan has had trouble in any mode. i have too many other things to cover right now but when i get time to go back to this,, i'm going to find out if this is the grimlin in the fan. it's not so easy to change that switch "unit", and there are no old subys in my area salvage yards to find now. they seemed maybe impossible to dissamble / service, i had to break it, and very $$$ new. i may have a couple still so someday when time is availableto do some trial & error with it again. thanks. Link to comment Share on other sites More sharing options...
robm Posted March 14, 2014 Share Posted March 14, 2014 I didn't have A/C on mine, it just energized with the ignition switch, then the speed selector would put power to the fan. The wiring diagrams with A/C are confusing. It sounds like you have simplfied it to the point wher it is workable. Link to comment Share on other sites More sharing options...
MilesFox Posted March 15, 2014 Author Share Posted March 15, 2014 I should have spare relays laying around, although some of them i have had for ages. No luck with thetm at the salvage yard unless it's 90's and later legacy impreza if they have the round relays. Link to comment Share on other sites More sharing options...
Gloyale Posted March 15, 2014 Share Posted March 15, 2014 I should have spare relays laying around, although some of them i have had for ages. No luck with thetm at the salvage yard unless it's 90's and later legacy impreza if they have the round relays. The square ones in Legacies/Impreza are interchangable with the old round ones. Link to comment Share on other sites More sharing options...
Gloyale Posted March 15, 2014 Share Posted March 15, 2014 I didn't have A/C on mine, it just energized with the ignition switch, then the speed selector would put power to the fan. The wiring diagrams with A/C are confusing. It sounds like you have simplfied it to the point wher it is workable. The ground side of the relay coil grounds out through the mode panel switch. Red/White wire..............If the selector is "off" the relay does not pass 12v through to fan. It's like that on all models....with or without A/C......since all US models were wired for A/C install. Link to comment Share on other sites More sharing options...
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