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2003 SLS, 99 Deville
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Discussion Starter #1
Driving a while back in my 03 SLS with about 98k, Noticed it was running a little hot, check the radiator fans and they where not running. Cool day so drove home and it cooled down to normal.

When home tried to get the fan to run by turning on the A/C to MAX and the fans did Not turn on!
Checked 134 pressure with the engine off, both high and low where about 50 lbs.
Observed the A/C Compressor with the engine running and the clutch was always engaged, no matter if the AC was set to run or not. Disconnected the elec connector at the compressor and the clutch disengaged, so it is an elec problem and not a mechanical prob with the compressor. Left it disconnected to search for the more serious fan problem.

Checked ALL the fuses in the engine compartment fuse block with an ohm meter, all fuses check Good. Checked the Fan 1 Relay (4 prong) and the Fan 2 Relay (2 prong), by trading them with other relays that I knew worked, No change. Check the 2 fuses under the back seat the I thought could be a problem and they are good.

There is No room for me to get my hand into the elec connector on the fans to check them, assume that both fans did not fail at the same time??

Consulted the wiring diagram and checked all the relays pulg-ins, All checked as I (novice) expected, except the Fan 1 – 85 goes to the PCM and did not know what to look for. Fan 2 – 85 and Coolingfan S/P(5 pin) – 85 show that they are connected together and to the PCM, they should show a short but they show an OPEN????

Consulted this FORUM and found out how to see the codes on the dash and reset them – THANKS

Checked the codes and it showed:
PDM 3932 & 3
IPC B1652
PCM P1545

Got a new S/P (5pin) Relay, installed it, cleared the codes, Started engine with MAX AC and no change, but the 1545 code did not reappear.

I Need big time help, does anyone have a clue for me????
Thanks

Richard
03 SLS – Great car otherwise
Castle Rock CO, this Seattle weather will not last forever
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,470 Posts
Have you studied the several sticky threads on these problems down in Engines; Northstar ? Cooling fan operation, cooling systems and gauges.

The fans (speed and wiring routing) are controlled by 3 relays - each fan on/off relay and fans in parallel (FAST) and series (SLOW) relay.

In parallel each fan receives full system voltage through the motor to ground. In series fan1 receives power, through the motor, over to fan2 input, through the motor, to ground - the resulting voltage drop is the SLOW speed.

Fans should run in SLOW. if any HVAC function set which calls for the A/C compressor to run. If no A/C function is set then fans are controlled by the ECT and PCM - SLOW at 224 degrees, FAST at 236. IF fans go to SLOW the engine cools to 213, fans shut off and the cycle repeats.
 

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Registered
2003 SLS, 99 Deville
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4 Posts
Discussion Starter #3
Submariner409 -
Thanks for the pic of the Temp Gauge, been looking for that info for some time.
I have read a lot about this prob on the internet and here, but having trouble getting to those 'sticky pages'
Have tested all 3 relays and they are OK, all fuses too
The HAVC is set for Max Cooling and the rad fans will NOT run.
Thanks
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,470 Posts
Have you checked the small relay feed and fan Maxi fuses in the underhoood fuse box ? There's a legend inside the top cover. (I see that you did) Check the grounds, ground box SP 104, and engine grounds.

For actual ground locations you'll need either a real GM/Helm service manual set from ebay or www.helminc.com or subscribe the car to www.alldatadiy.com.

The stickies are at the top of this (Seville) main threads page and at the top of any forum main page - several stickies, then the list of these threads. Scroll to Cadillac Forums, Item Specific, Engines; Northstar. The first 6 or 8 threads you see are stickies.

If you have only this Seville forum bookmarked you are missing 98% of what's in the site. Use this to get the big picture:

http://www.cadillacforums.com/forums/forum.php

Here's your fan circuit.
 

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2003 SLS, 99 Deville
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4 Posts
Discussion Starter #5
I have checked the 87 pin (A11 on your diagram) on the 5 pin (SP)relay and it is a dead short (0 ohms), also Fan Relay 1, 87 pin (B11) connected to SP relay 87a and the left fan show just a few ohms. I do not know where the SP104 is but think the grounds are OK.

I have checked all the 3 relay receptacles and think they are all OK, except SP relay C11 and the Cool Fan 2 relay which look like they are connected together and to the PCM but do NOT show a short???

Did follow your link to the main part of the forum and found the stickies you referenced. Lots of stuff. Read most of the post that I thought where related to my problems and found a few clues but NO results.

Thanks for all your help!!!!
 

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2003 SLS, 99 Deville
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4 Posts
Discussion Starter #6
I gave UP !! First time
Took it to a pro - they found that rodents had chewed the wires going into the PCM and that kill the 2 fans and did the ac compressor dead.
THANKS for all of you who helped and posted the wiring diagram and Temp Gauge, that helped a lot.

Richard
 
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