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sprinkles08
sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 21601
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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2002 Grand Cherokee 4.0L 4X4 w HD trailer pkg, w/elec fan

Customer Question

2002 Grand Cherokee 4.0L 4X4 w HD trailer pkg, w/elec fan and eng clutch fan. I don't believe the elec fan is kicking in with AC on, but it does come on with engine temp reached normal 195 temp. Isn't the elec fan suppose to come on when the AC is turned on, not just when the engine reaches running temp?
JA: How many miles on the car? Is it the original transmission?
Customer: 176K, and yes original trans.
JA: When was your last tune up?
Customer: a year ago, maybe 10K
JA: Are you hoping to fix this yourself?
Customer: yes
JA: What have you tried so far?
Customer: had ac serviced and they said it seemed to be ok. AC fan does run with a roar when hooked direct to 12V.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Jeep Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Jeep
Expert:  Kurt Kennedy replied 6 months ago.
The fan should come on with the AC setting on High. Have you tried to set the AC to max cold and see if that works? let me know and we can go from there.Thanks!
Customer: replied 6 months ago.
My elec fan does not come on until the engine temp reaches its normal operating temp and only runs to cool the engine down slightly. It does not come on just by running the vehicle and turning on the AC to max.I have changed the fan relay --under the pass headlight; the AC clutch relay in the under hood fuse box, the AC high press /transducer switch. I don't see a low press switch that some posts say is on the accumulator, or an AC cycling clutch switch, that I also don't see. I am almost ready to replace the complete elec fan motor assy, but it does work by engine temp, and it does blow fast when wired direct to 12V. MY ACTUAL PROBLEM is that the Jeep cranks and cranks and doesn't what to start after it has been driven for awhile with AC on and the temp gauge stays just around 195 and under 210. It has caused my camshaft and crankshaft sensors to show codes and have been replaced by a dealership techs.
Customer: replied 6 months ago.
I'm still having starting problems even after those sensors were replaced. It just cranks and cranks and sputters a little and then starts and seems to run rough for a few seconds after starting "when the engine is at operating temp, after being driven for a while" This engine always starts on the 1st crank when its cool, and runs great, does not seem to need a tuneup or have fuel problems....
Expert:  sprinkles08 replied 6 months ago.
Hello and welcome to JustAnswer!Are any fault codes currently setting?
Customer: replied 6 months ago.
No current codes.
Expert:  sprinkles08 replied 6 months ago.
Do you have a fuel pressure gauge?
Customer: replied 6 months ago.
no fuel press gauge. Just drove it again after replacing the elec fan assy and thermostat and engine temp gauge. Did not use AC at all. Drove for about30-45 minutes maybe 30 miles, on open rural roads(not stop & go). Temp gauge stayed in normal range. came back home pulled into garage, shut it off and tried to start again. Engine just cranked and cranked, sputtered a little, then a light "pop", but didn't start. Tried again, same. And again, same; then just cranked even longer, made some popping and knocking noises and then started, but rough for about a minute, then smoothed out. I shut it off and let it sit to cool down abit, (maybe 30 minutes). Then it started fine on the 1st crank and ran smooth.Something is still breaking down when it gets up to operating temp. But it seems to run great while driving at the operating temp; it's just when you shut it off and try to immediately start it again, even when pulling into a gas station for a fill up.This is my wife's vehicle and she doesn't want to drive it for fear she'll get somewhere and it won't start, and she won't know what to do.
Expert:  sprinkles08 replied 6 months ago.
What you're describing is the common symptom of vapor lock. When the engine is hot and you shut it off, the high underhood heat will elevate fuel pressure in the rail, sometimes to the point of boiling. This can cause fuel to be pushed back to the tank due to a weak check valve in the fuel pump, or in this case the filter/regulator is also a possibility. I would recommend replacing the filter/regulator first based on the symptoms.