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68 DVC, 96 FLTWD Brgm, 11 CTS Premium (two)
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Discussion Starter #1
Hi, My Fleetwood Brougham has RPO V03, extra capacity cooling - a more powerful 250W secondary fan motor. But it's the Primary or right one I'm asking about.

The RH fan (pass side, Primary cooling fan) is not turning on. Isn't it supposed to turn on when the climate control is on and the compressor is running?
 

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Discussion Starter #3 (Edited)
So when IS it supposed to turn on?? The manual says it should come on after a certain pressure 225PSI in the AC system is reached. The secondary turns on at 248PSI so the primary should turn on first - correct?
 

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96 Fleetwood, 94 Fleetwood, 07 CTS, & 94 Caprice Wgn
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I wouldn't try to over think the fans etc.; system is simple and works good. The primary fan comes on at 225 degrees. The secondary fan comes on at 232 degrees. I may not be exact on the temperatures. The secondary fan also comes on when the AC is turned on. If it is low on freon, it will not turn on. No need to worry about pressures.
 

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Discussion Starter #5 (Edited)
The car's ETC never got that hot. At least not today.

However, if the secondary fan turns on when the AC pressure is at or above 248 PSI, and it DID turn on with the AC on ( and it cycled off intermittently) but the Primary is supposed to turn on at 225 PSI, then WHY DIDN'T THE PRIMARY FAN COME ON FIRST???

As far as engine coolant temp (ETC) is concerned, the primary is supposed to turn on at 107c 225F, and the secondary at 111c / 232F But as I noted the coolant never got that hot. 100c / 212F was the hottest it got while I was tracking it.

However, the AC should have triggered the Primary fan first and that fan never turned on.
 

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It is the primary fan that comes on first (ahem, being primary and all) and it also would come on anytime when the A/C is on. The secondary fan may never come on unless the car gets hot enough. The secondary fan typically comes on in hot weather in stop and go traffic.
 

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For future searchers PS is the primary and comes on at a set temp, which is lower than the DS secondary does. Separate from that the primary is triggered after A/C is on and reaches a set pressure. The 2ndary comes on after the A/C is on and reaches a yet higher pressure.

For V03 the PS primary is either 100w or 150w. It doesn't matter, just replace with correct part no. The DS 2ndary is more watt and much bigger size (240w IIRC). It's not important, just replace with correct part no.

A couple of important things after all that:
-The relays and wiring on our cars are weak. Check them for failure and burnt connectors before anything else.
-Unplug the ECT on the WP and both fans must turn on. I think the car runs crappy when you unplug it running, but it'll point you to a failed 'something' if either and both fans aren't turned on after disconnecting the ECT plug.

I discovered a primary not turning on even with the 2ndary running (much like Mike above). I swapped the relays and still no primary. But the 2ndary still ran. So, I spent way too long with continuity checks before discovering a melted primary fan connector. Jumpered that and the primary ran fine. With only 75k the radiator had blown a sidetank which started all the investigating in the first place. So the primary not running at all had apparently been stressing the system for some time.


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