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Unread 08-19-2006, 11:45 PM   #1
jeremypittman
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coolant fan not powering on with ac

Just picked up a 98 GC limited with the 5.9 ltr.... The radiator fan doesnt come on with the ac being powered on... The radiator fan does work just fine with the heat of the coolant turning it on and off. since the fan doesnt power on with the ac, I dont have any cold air when I'm setting still.

Any ideas? Relay maybe?

thnx

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Unread 08-20-2006, 12:18 AM   #2
SJZ
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Quote:
Originally Posted by jeremypittman
Just picked up a 98 GC limited with the 5.9 ltr.... The radiator fan doesnt come on with the ac being powered on... The radiator fan does work just fine with the heat of the coolant turning it on and off. since the fan doesnt power on with the ac, I dont have any cold air when I'm setting still.

Any ideas? Relay maybe?

thnx
http://www.netpreview.com/98zjcooling.pdf
What you're looking for starts on page 8.
Here's the wiring diagram:
http://www.netpreview.com/98zjwiring.pdf
Sheet: 8W-30-31
Looks like the low speed fan comes on with the AC. When you say it works fine with cooant temperature, I wonder if you are seeing high speed only? Maybe your low speed relay or motor winding is NG. Sould be easy enough to troubleshoot, now that you know how it works (after reading PDF).
-Steve
__________________
-Steve
"Those who hammer their guns into plows, will plow for those who do not." -Thomas Jefferson
___________________________________________
'98 ZJ Laredo 5.2 Selec-Trac (249 to 242 swap)
'05 KJ Limited 3.7 Selec-Trac
'94 ZJ Limited 5.2 Q-Trac- sold, after 17 years
'67 International Harvester Scout 800; 345ci V8,T18 4spd, Dana 20 TC
'06 Chrysler 300C SRT8 6.1L

Last edited by SJZ; 08-20-2006 at 12:36 AM..
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Unread 08-20-2006, 12:22 AM   #3
jeremypittman
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that would make sence... I'll start with the low speed relay...

Thanks, If you think of anything else just drop me an email....
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Unread 08-20-2006, 12:43 AM   #4
SJZ
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Quote:
Originally Posted by jeremypittman
that would make sence... I'll start with the low speed relay...

Thanks, If you think of anything else just drop me an email....
Check your PM.
__________________
-Steve
"Those who hammer their guns into plows, will plow for those who do not." -Thomas Jefferson
___________________________________________
'98 ZJ Laredo 5.2 Selec-Trac (249 to 242 swap)
'05 KJ Limited 3.7 Selec-Trac
'94 ZJ Limited 5.2 Q-Trac- sold, after 17 years
'67 International Harvester Scout 800; 345ci V8,T18 4spd, Dana 20 TC
'06 Chrysler 300C SRT8 6.1L
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Unread 08-20-2006, 11:27 AM   #5
jeremypittman
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Well I took the high speed relay and plugged it into the low speed connector and did the same with the low speed relay into the high speed connector. The fan still didnt power on with the ac... I am going to let it idle and see if it powers on with the coolant temp. If it does, and I'm thinking correct this would indicate that both relays are good.

How would one trouble shoot the low speed winding in the fan motor?
Only way I can think of is to check with an ohm meter..

Jp

Quote:
Originally Posted by SJZ
http://www.netpreview.com/98zjcooling.pdf
What you're looking for starts on page 8.
Here's the wiring diagram:
http://www.netpreview.com/98zjwiring.pdf
Sheet: 8W-30-31
Looks like the low speed fan comes on with the AC. When you say it works fine with cooant temperature, I wonder if you are seeing high speed only? Maybe your low speed relay or motor winding is NG. Sould be easy enough to troubleshoot, now that you know how it works (after reading PDF).
-Steve
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Unread 08-20-2006, 02:14 PM   #6
jeremypittman
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Join Date: Aug 2006
Location: nc
Posts: 26
Found the low speed winding in the motor to be at fault. Relays are putting power to the motor when they should but fan doesnt move. Checked to ohms on the high speed winding and got "0" checked on the low speed and it read open....


Now on my way to get a new fan motor... Thanks for all the help



Quote:
Originally Posted by jeremypittman
Well I took the high speed relay and plugged it into the low speed connector and did the same with the low speed relay into the high speed connector. The fan still didnt power on with the ac... I am going to let it idle and see if it powers on with the coolant temp. If it does, and I'm thinking correct this would indicate that both relays are good.

How would one trouble shoot the low speed winding in the fan motor?
Only way I can think of is to check with an ohm meter..

Jp
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Unread 08-20-2006, 02:31 PM   #7
SJZ
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1998 ZJ 
 
Join Date: Feb 2006
Location: . . . . . . . . . . . . . . . A shining city upon a hill
Posts: 1,498
Quote:
Originally Posted by jeremypittman
Found the low speed winding in the motor to be at fault. Relays are putting power to the motor when they should but fan doesnt move. Checked to ohms on the high speed winding and got "0" checked on the low speed and it read open....


Now on my way to get a new fan motor... Thanks for all the help
Better make sure that is not merely a poor connection (i.e. motor wire to conector) before buying a motor.
-Steve
__________________
-Steve
"Those who hammer their guns into plows, will plow for those who do not." -Thomas Jefferson
___________________________________________
'98 ZJ Laredo 5.2 Selec-Trac (249 to 242 swap)
'05 KJ Limited 3.7 Selec-Trac
'94 ZJ Limited 5.2 Q-Trac- sold, after 17 years
'67 International Harvester Scout 800; 345ci V8,T18 4spd, Dana 20 TC
'06 Chrysler 300C SRT8 6.1L
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Unread 08-21-2006, 07:48 PM   #8
jeremypittman
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Location: nc
Posts: 26
Well checked the price on the new fan motor ouch $300+ complete asy. For right now I'm going to re-wire it so that when the low relay powers it will run the fan in the hi speed.
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Unread 08-21-2006, 08:28 PM   #9
SJZ
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Posts: 1,498
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__________________
-Steve
"Those who hammer their guns into plows, will plow for those who do not." -Thomas Jefferson
___________________________________________
'98 ZJ Laredo 5.2 Selec-Trac (249 to 242 swap)
'05 KJ Limited 3.7 Selec-Trac
'94 ZJ Limited 5.2 Q-Trac- sold, after 17 years
'67 International Harvester Scout 800; 345ci V8,T18 4spd, Dana 20 TC
'06 Chrysler 300C SRT8 6.1L
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