Cooling Fans Question - 986 Forum - The Community for Porsche Boxster & Cayman Owners

baldymech · 05-07-2008, 02:40 PM

I noticed today that the left front cooling fan is not running, but the right one is running. When I turn on the a/c both fans come on. It sounds like they are on high speed. I understand the fans have a high and low speed. The car is a 2000 with 32000 miles and doesn't appear to be overheating. I would like to fix it before the hot weather gets here.

Thanks,
baldymech

kabel · 05-07-2008, 02:52 PM

likely culprit is the fan resistor or ballast resistor that is hardwired in by the fan, about the size of a cigar.

Thread on RennTech: http://www.renntech.org/forums/index.php?showtopic=15680&hl=resister

pic courtesy of Loren over on RennTech:

Fletch986 · 05-07-2008, 06:38 PM

+1 with Kabel (and great picture). the low speed setting is gone and i'm told that it's quite a drain on the charging system for the fan to go from off directly to the high speed setting. fwiw

Lil bastard · 05-07-2008, 08:13 PM

Good call on the Ballast Resistor, but it's not the only possibility.

The Cooling Fans also depend on both a high-speed and a Low-speed relay - each fan has one of each.

They are relays #s 19 (Lft. low), 20 (Lft. high), 21 (Rht. low), 22 (Rht. high).

Since you cannot test the Ballast Resistor, only replace it, it's best to 1st test the relays to make sure their not the problem. Switch them around (the same type Relay is used for both high and low-speed) and see if the problem doesn't reverse itself. If not, it's the resistor.

baldymech · 05-08-2008, 02:56 PM

Thanks for the info and pictures. I swapped the relay with the fog lite relay same p/n
The relay checked good. Can you just buy a new ballast resister or do you have to
buy a new fan assembly .Great forum .

Thanks again

Baldymech

Lil bastard · 05-08-2008, 03:39 PM

You can buy just the ballast resistor - PN#996.616.101.00 . You also need some heat shrink tubing, electrical tape. You can use a crimp connector (2), but I don't recommend these as they aren't the best way to make a splice. The swap is pretty simple.

silver arrow · 05-08-2008, 04:30 PM

Great info, I just noticed the same thing in my 2000 Boxster too.

baldymech · 05-20-2008, 03:50 PM

I replaced the left side ballast resister, now both fans have a low speed.

Thanks again for your info and pics

Baldymech.

kabel · 05-20-2008, 06:57 PM

Great! Thanks for reporting back.

Dragonwind · 05-21-2008, 02:32 AM

I noticed neither of my fans have a low speed. It isn't overheating but in warmer weather it has been getting a little higher than normal and I can detect an antifreeze smell from the front. I was planning on cleaning the radiators and changing the spring clamps to worm type to take care of that problem this weekend. The fans do come on at high speed and with the AC on. Where might be the best place to get a couple in a hurry?
Thanks
Chris