Late model Fan Relay queestions
06-22-2005, 03:54 PM
#1
Instructor
Thread Starter
Join Date: Jan 2004
Location: Philadelphia, PA
Posts: 190
Likes: 0
Received 0 Likes
on
0 Posts
Late model Fan Relay queestions
Have a few questons about Fan relay. The car is an '88 951 (non S).
Had it on road for about 500 miles. Replaced both cooling fans ( after picking up 2 duds used ), replaced fan relay 2X (turned out original worked). While working on car last week I noticed only one fan was running, and car was pretty hot, not red zone hot, ut hot. Also the cooling fan would stay on high for about 3 or 5 mis after driving -- lots of stares as I walk away from car that sounds like it's still running. NO boilover or steaming, system bled, etc.
Was charging my AC, and noticed the expansion tank was weeping coolant. obviously the car was running hotter with ac on, no surprise, but one fan on high, + 93F was too much for it. Shut car off, let fan run for 15 or so minutes.
Now I'm REALLY curious about why both fans aren't working.
DO Clarks Garage test:
-Only one fan runs on LO when thermo switch jumpered.
-NO fans run when jumpered to HI
-one fan runs on LO when AC on, same fan runs on HI when car running and AC on
All fuses OK, both fans are ok ( swaped plugs between them to make sure), At this point I think it's the relay, but is there any way I can make sure? I've got 2 others, but their part numbers are different from the one in the car, and swapping them in they seem to give some of the same behavior, running only one fan. The other relays also do weird things with the AC.
Anyone have any ideas? How about a KNOWN working latemodel fan really cheap?
-Heybiff
-EDIT:
When jumping the thermo switch to run fans on LO, the one fan would kick up to HI after 3 or so secs. This did NOT happen with car ignition ON, and AC switch ON, then the fan hummed on LO. I can't say I've ever hear the fans run on LO since I put them in.
Had it on road for about 500 miles. Replaced both cooling fans ( after picking up 2 duds used ), replaced fan relay 2X (turned out original worked). While working on car last week I noticed only one fan was running, and car was pretty hot, not red zone hot, ut hot. Also the cooling fan would stay on high for about 3 or 5 mis after driving -- lots of stares as I walk away from car that sounds like it's still running. NO boilover or steaming, system bled, etc.
Was charging my AC, and noticed the expansion tank was weeping coolant. obviously the car was running hotter with ac on, no surprise, but one fan on high, + 93F was too much for it. Shut car off, let fan run for 15 or so minutes.
Now I'm REALLY curious about why both fans aren't working.
DO Clarks Garage test:
-Only one fan runs on LO when thermo switch jumpered.
-NO fans run when jumpered to HI
-one fan runs on LO when AC on, same fan runs on HI when car running and AC on
All fuses OK, both fans are ok ( swaped plugs between them to make sure), At this point I think it's the relay, but is there any way I can make sure? I've got 2 others, but their part numbers are different from the one in the car, and swapping them in they seem to give some of the same behavior, running only one fan. The other relays also do weird things with the AC.
Anyone have any ideas? How about a KNOWN working latemodel fan really cheap?
-Heybiff
-EDIT:
When jumping the thermo switch to run fans on LO, the one fan would kick up to HI after 3 or so secs. This did NOT happen with car ignition ON, and AC switch ON, then the fan hummed on LO. I can't say I've ever hear the fans run on LO since I put them in.
06-22-2005, 06:56 PM
#2
Rennlist Member
Yo biff, you seem pretty technically inclined so here's a procedure to check your relay.
Looks like you do have a bad relay. But also your system sounds like it is running hot. I'm running with a hurt relay right now and only one fan works in slow speed, but it doesn't run in high speed hardly ever. And when it does, it cools it rather quickly. I suspect you have other issues like a clogged radiator. But fix the relay first and see how it acts.
Looks like you do have a bad relay. But also your system sounds like it is running hot. I'm running with a hurt relay right now and only one fan works in slow speed, but it doesn't run in high speed hardly ever. And when it does, it cools it rather quickly. I suspect you have other issues like a clogged radiator. But fix the relay first and see how it acts.
06-23-2005, 11:33 AM
#3
Addict
Rennlist Member
Rennlist Member
Join Date: Jun 2001
Location: Albuquerque, New Mexico
Posts: 168
Likes: 0
Received 0 Likes
on
0 Posts
My problem (only one fan running), was that the push on connector at the non running fan had the crimp on female blade contact pushed back into the two conductor connector houseing. There is a little little metal tab on the connector which keeps the connector locked into the plastic housing. Mine had been bent backwards and would allow the crimp on connector to back out of the housing when putting the connector on. After straighting out the tab, the connector could be pushed on with out the crimp on metal connector backing out. I amost bought the relay for $130 bucks, glad I didn't because it wasn't the problem.
You can do a quick check of your fans by them selves by jumpering from the + side of the battery to the V1, 2 and M1, M2 slots in the fuse box with the fan relay removed. That will tell you if your fans will run in both high and low speeds (my passenger fan wouldn't run at either speed).
Jon
You can do a quick check of your fans by them selves by jumpering from the + side of the battery to the V1, 2 and M1, M2 slots in the fuse box with the fan relay removed. That will tell you if your fans will run in both high and low speeds (my passenger fan wouldn't run at either speed).
Jon
