2001 cooling fan amp draw? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > 2001 cooling fan amp draw?

Savvy Aluminum BumpersIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed LineThe RuffStuff "I can't go to EJS" Sale!

Reply
Unread 09-14-2013, 10:09 AM   #1
mar-tay1
Registered User
 
Join Date: Sep 2013
Location: daly city, ca
Posts: 3
2001 cooling fan amp draw?

helping a friend with his wifes 2001 grand cherokee. the fan relay smoked and has been replaced twice so I checked the amp draw of the aftermarket fan and it's pulling 19 amps solid. Seems like too much, really arcs when you jump it, what amp draw should it have? Is there a way to bypass the relay so that the check enjgine light doesn"t come on? Thanks!

mar-tay1 is offline   Reply With Quote
Unread 09-14-2013, 02:11 PM   #2
Jaspah
Registered User
2002 WJ 
 
Join Date: Oct 2012
Location: Morrisville, New York
Posts: 208
Quote:
Originally Posted by mar-tay1 View Post
helping a friend with his wifes 2001 grand cherokee. the fan relay smoked and has been replaced twice so I checked the amp draw of the aftermarket fan and it's pulling 19 amps solid. Seems like too much, really arcs when you jump it, what amp draw should it have? Is there a way to bypass the relay so that the check enjgine light doesn"t come on? Thanks!
Honestly sounds like the fan itself is going bad. The reason the fan relays burn out so quickly on the OEM electrical fan is that the fan is taking too much amperage to spin.
Jaspah is offline   Reply With Quote
Unread 09-14-2013, 03:14 PM   #3
Brakeman62
Registered User
2001 WJ 
 
Join Date: Feb 2012
Location: Omaha, Nebraska
Posts: 57
X2
Brakeman62 is offline   Reply With Quote
Unread 09-14-2013, 03:44 PM   #4
mar-tay1
Registered User
 
Join Date: Sep 2013
Location: daly city, ca
Posts: 3
Thats what I was thinking, looks like too many amps through the relay. Problem is, it is a new fan. I purchased another relay and am a little hesitant to put it in.
mar-tay1 is offline   Reply With Quote
Unread 09-14-2013, 08:16 PM   #5
greeky510
Registered User
2000 WJ 
 
Join Date: Apr 2013
Location: norwalk, ct
Posts: 115
How did you test for the amp draw?

Sent from AutoGuide.com App
greeky510 is offline   Reply With Quote
Unread 09-15-2013, 06:45 AM   #6
Cobra Jeep
Registered User
1993 YJ Wrangler 
 
Join Date: Aug 2005
Location: , Alabama
Posts: 1,177
I recently bought a snap on multimeter and bought the amp clamp to go with it. It simply plugs into the multimeter and then it has a clamp you put around the wire (kinda like a timing light) and will measure the amps running through the wire.
I was playing with it and decided to test the fan on my 99 WJ. It showed 22 amps while running. The fuse/relay box under the hood has a 40 amp fuse for the fan, so I figure mines fine. The relay is good too.
__________________
'93 YJ 4.0L, AX-15, NP-231HD/SYE, 8.8in rear, OME 2.5 lift, WJ knuckle/brake conversion, hydroboost. Warn M10000 winch. Hope to some day build a stroker for it.

'79 Cherokee Chief, 401 MPFI fuel injection, T-18/D-20 and hydroboost. Otherwise stock.
Future mods: NV4500, NP205, high pinion D60 front and smooth bottom D60 rear, e-lockers front & rear. SOA with 35X12.50's
Cobra Jeep is offline   Reply With Quote
Unread 09-16-2013, 09:02 AM   #7
mar-tay1
Registered User
 
Join Date: Sep 2013
Location: daly city, ca
Posts: 3
thanks cobra jeep that's what I was looking for. My Fluke meter shows about 19 amps or so while running, so I'm in the ballpark. I'm going to mount a separate relay,where you can get to it, so all the load goes through that rather than the factory relay, that way if there is a problem it will be simple to jump the fan if need be, and if it smokes, it's 5 dollars. THANKS AGAIN!
mar-tay1 is offline   Reply With Quote
Unread 09-16-2013, 10:39 AM   #8
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,043
Just a few words about substituting a standard relay for the stock relay.

The stock relay (a pulse-width modulated relay) is a solid state device, not at all like a standard electromechanical relay. A signal from the PCM (a pulsating 5V signal) switches on/off the current through the relay; it does not energize a coil to open or close a set of contacts. The variable pulse-width of the signals sent from the PCM allows the fan speed to vary according coolant temperature. It's doubtful that a standard electromechanical relay can operate on the 5V pulse-width signal, and if it could, the frequent opening and closing of the contacts would probably cause them to degrade quickly. If the PCM signal is not or can not be used, you can count on a code being thrown.

Some people have had success mounting the stock relay on a heat sink in an area with good air flow. You might consider doing that. By extending the wires, you could mount the relay almost anywhere for convenience sake.
__________________
2001 WJ Limited with Quadra-Drive, Kenne Bell Supercharger, 3-inch Kolak exhaust, Stillen rotors (F/R) and MM pads, Addco sway bars (F/R).
rm2001wj is offline   Reply With Quote
Unread 09-16-2013, 05:37 PM   #9
Cobra Jeep
Registered User
1993 YJ Wrangler 
 
Join Date: Aug 2005
Location: , Alabama
Posts: 1,177
Yep, a standard relay can not be substituted for a PWM relay that the WJ uses. Hooking up a regular relay in place of a PWM relay will create a firestorm inside the regular relay and burn it out in very short order.
Think of pulse width modulating as basicly it turning on and off really fast. Doing this, can allow the fan to speed up slowly and avoid the sudden high amp draw when it first kicks on and speeds up like if you were using a regular relay. And also can be used to control its speed.
__________________
'93 YJ 4.0L, AX-15, NP-231HD/SYE, 8.8in rear, OME 2.5 lift, WJ knuckle/brake conversion, hydroboost. Warn M10000 winch. Hope to some day build a stroker for it.

'79 Cherokee Chief, 401 MPFI fuel injection, T-18/D-20 and hydroboost. Otherwise stock.
Future mods: NV4500, NP205, high pinion D60 front and smooth bottom D60 rear, e-lockers front & rear. SOA with 35X12.50's
Cobra Jeep is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.