Pilgrim Posted June 19, 2011 Share Posted June 19, 2011 (edited) I'm having a problem with my 1983 280ZX Turbo. The blower works fine on vent and heat, but after just a few minutes (sometimes only 2 or 3) with the AC on, the blower fan stops working. (EDIT: With more testing, I learned this happens regardless of whether AC is on - it happens even if just the fan is running!) The AC compressor still runs, but the dashboard blower fan which delivers the cooled air inside the car stops. Turning the AC off doesn't bring the fan back to life; it will only start working again after the car has sat for a few hours. This has happened 4 or 5 times. No fuses have ever blown, including the stealth glass tube fuse that's mounted under the blower motor. After sitting for a few hours, the fan works again. But hop into the car when it's hot and crank up the AC - and the fan runs for a couple of a minutes, then shuts off. If the car sits for an afternoon or overnight, the fan works again. The way this reasons out to me, it seems like running the fan must make some component associated with the blower fan heat up and fail. When it cools off, the fan runs again. Does this diagnosis sound likely to you? If so, what component do you suggest I check? I was thinking of the amplifier mounted under the blower, but it is used all the time - it operates both with and without AC. Edited June 22, 2011 by Pilgrim Quote Link to comment Share on other sites More sharing options...
FricFrac Posted June 20, 2011 Share Posted June 20, 2011 Is the thermal sensor by the glove box working properly? Quote Link to comment Share on other sites More sharing options...
FricFrac Posted June 20, 2011 Share Posted June 20, 2011 Oh and don't forget the FSM at www.xenons130.com as well for troubleshooting.... Quote Link to comment Share on other sites More sharing options...
JES0486 Posted June 20, 2011 Share Posted June 20, 2011 I had the same problem in my 82 280zx if you check and nothing else works. When the A/C fan was on it would cut off like the way you describe yours; but one day I went into the fuse box and accidently hit the fuse for the A/C fan an it came back on. Everytime it would shut off I would jiggle the fuse and it would start back up. This means that I had a loose/faulty connection at the fuse box for the fan. Hope it helps with your problem. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted June 21, 2011 Author Share Posted June 21, 2011 I have the manual AC system and a factory service manual...wasn't aware there was a thermal switch near the glove box. Will check manual. Every fuse relating to AC and fan has been removed, tested and reinserted - twice. Not bad fuse contact...but will jiggle things and see if the problem occurs or disappears. Remember that the AC works properly and the compressor engages, it's only the dashboard blower fan that shuts off. I can tell from the load on the motor and the idle speed that the AC compressor is still engaging. Quote Link to comment Share on other sites More sharing options...
JES0486 Posted June 21, 2011 Share Posted June 21, 2011 I have the manual AC system and a factory service manual...wasn't aware there was a thermal switch near the glove box. Will check manual. Every fuse relating to AC and fan has been removed, tested and reinserted - twice. Not bad fuse contact...but will jiggle things and see if the problem occurs or disappears. Remember that the AC works properly and the compressor engages, it's only the dashboard blower fan that shuts off. I can tell from the load on the motor and the idle speed that the AC compressor is still engaging. I have the same good working manual AC with an engaging comp but never checked a thermal switch though. It was always real twitchy I finally confirmed it when I removed the fuse block, removed the wires for the AC blower hooked them up strait (w/out fuse) and it ran without anymore gremlins. After a few days of running without a fuse to make sure that was it I throughlt cleaned connections from any corrosion and resoldered the wires back in. Worked fine since. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted June 22, 2011 Author Share Posted June 22, 2011 I checked all wiring diagrams - none show a thermal sensor for the manual AC system...so that's not it. It's also not the AC fuse in the fusebox, because....I need to correct an error. This does NOT happen only when AC is on - it happens regardless of AC. All I have to do is turn the fan up and it will shut off within 5 minutes of run time. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted June 22, 2011 Share Posted June 22, 2011 Correct the manual doesn't have the thermal sensor. With the updated info I'd say either the fan itself has a bad solder connection/connector or in the harness to the fan as the first suspect. Do you have a fan unit you can swap out? You can also try running the fan by itself and tap around with the handle of a screw driver, etc to see if you can induce the fault. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted June 24, 2011 Share Posted June 24, 2011 Don't both manual and automatic a/c systems use a "blower amplifier" mounted to the case next to the motor? If so, it could be having issues. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted July 3, 2011 Author Share Posted July 3, 2011 (edited) The amplifier is an excellent idea, - I have a spare and tried swapping. Still has the problem. Dang. Best candidate according to FSM and tests is the blower relay, a 4-pin relay mounted on the underside of the blower housing next to the amplifier. Need to replace it; called Courtesy Nissan but they had trouble identifying it and no call back yet. I'll have to rattle their cage Tuesday. Edited July 4, 2011 by Pilgrim Quote Link to comment Share on other sites More sharing options...
palladin Posted December 4, 2011 Share Posted December 4, 2011 You ever fix this. PM me if not. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted December 5, 2011 Author Share Posted December 5, 2011 Good suggestion to check the fan speed rheostat - but I replaced it, and checked the contacts as well using the process in the factory manual. I don't believe it's the problem. Quote Link to comment Share on other sites More sharing options...
palladin Posted January 7, 2012 Share Posted January 7, 2012 I take it you got it fixed. There is a fuse on the underside of the blower. Be advised, I had a bad rheostat....when you initially clicked it, it started the fan. If yours is going...it could be intermittant. You said you replaced it...perhaps also with the "new" one. Otherwise trace the wire from the switch to the fan. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted January 7, 2012 Author Share Posted January 7, 2012 (edited) I take it you got it fixed. There is a fuse on the underside of the blower. Be advised, I had a bad rheostat....when you initially clicked it, it started the fan. If yours is going...it could be intermittant. You said you replaced it...perhaps also with the "new" one. Otherwise trace the wire from the switch to the fan. Unfortunately no, the car is still sitting while I tend to other issues. It has been down for at least three months, which is a bummer. Good call on the fuse...it's one of those hidden "gotchas" which can be hard to find. I know about it and have checked it, but I'll re-check. Right now I have no fan, no AC compressor engagement...nothing. Not the result I was hoping for. I need to spend some time with the wiring diagrams and see where these circuits travel. Before installing the new rheostat and AC switch I tested...the AC switch inside the climate control box tested good for contact closure, and the rheostat tests good as per the test procedure in the shop manual (it's also accessible by removing the center AC vent, unplugging the harness from it, and using a multimeter to check function.) I believe the problem is elsewhere in the wiring, but I'm still stumped as to where. The fact that I have (1) no fan, and (2) no AC compressor engagement indicates to me that there are two aspects to the problem. Initially when I lost fan function, the AC still engaged - but neither system works now. Edited January 7, 2012 by Pilgrim Quote Link to comment Share on other sites More sharing options...
macs_5 Posted January 30, 2012 Share Posted January 30, 2012 My 82 did this same thing, N/A model 5 speed with manual ac. what I found after several weeks of hot summer trouble shooting was that the relay mounted below the fan in front of the glove box, had overheated and the terminals were spread. I thought at first that it was the amplifier also, but tested it out and found it okay. In any case, check the connectors and pins for evidence of overheat and repair according to need. Hope this helps. It really is kind of an insidious problem, intermittent shorts are always fun. I won't even mention my fuel injector troubleshooting and final repair after numerous rounds of trouble shooting everything at least 3 times. regards, mac Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted February 1, 2012 Author Share Posted February 1, 2012 Definitely worth looking at! I'll check it and let you know how it did. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted March 3, 2012 Author Share Posted March 3, 2012 There's good news...not necessarily a permanent fix, but at least a temporary positive note. Last week I dug into the ZX and checked wiring, and darned if I didn't find a blown fuse. It was the 20A fuse on the bottom right corner of the fusebox; I didn't check the label on the slot, but I replaced the fuse and my blower fan and AC compressor both work!! I drove it around town and on the highway for more than 1/2 hour and everything continued to work. Do I think the problem is solved? Not really. I think I fixed a symptom, but there's a reason the fuse blew - and that reason is the real cause. However, I'll live with this for the time being. I suspect the test will come when the weather warms up, as the original problem occurred when days were hot. It's possible that when I replaced the wiring harness for the blower fan and AC control unit that I blew the fuse - and if so, I'll be a happy guy. But after six months of down time, pulling the dash and replacing wiring and vacuum hoses, I'm damn glad to have it driveable again!! Quote Link to comment Share on other sites More sharing options...
ZUL8TR Posted March 4, 2012 Share Posted March 4, 2012 FWIW, I had a somewhat similar problem. It was intermittent, then eventually stopped work all together. Replaced the switch and it was all better. Quote Link to comment Share on other sites More sharing options...
Pilgrim Posted March 4, 2012 Author Share Posted March 4, 2012 Which switch? Rheostat for the blower? (The AC switch which mounts inside the control unit was replaced with the wiring and it tested OK.) It's not a bad thought - I have replaced it once, a couple of years ago. It tests OK but intermittent problems can be like that. Quote Link to comment Share on other sites More sharing options...
ZUL8TR Posted March 4, 2012 Share Posted March 4, 2012 The switch in the control unit. Where you turn the fan on/off and control fan speed. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.