Question about 1999 Jeep Grand Cherokee

1 Answer

My cooling fan has no power even when wired directly to ignition.

When I first got my Cherokee 5 years ago, I had to replace the PCM within a month. Since then I've had to replace the fan relay at least once a year. Now my cooling fan has quit working, even after replacing the fan relay again and installing a new thermostat. It was wired directly to the ignition and worked sometimes, but is now completely dead. I'm not mechanically inclined so I have no idea exactly what parts I'll need to replace the fan. Does it come as all 1 kit? Could it be anything else other than the fan just fried out?

Posted by on

  • Sarah Feb 22, 2012

    It's 4WD, 6 cyl, no tow package

×

Ad

1 Answer

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

You can test ur fan with running" leads" or wires. a + and- from fuse box straight to fan wires, putting a on and off switch in between. its to check is fried or not. switch in line really not needed but it works

Posted on Feb 22, 2012

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Procedure to diagnose dtc p0526 2005 gmc envoy 4.2L


DTC P0526 Cooling Fan Speed Sensor Circuit

Circuit Description
The powertrain control module (PCM) uses the cooling fan speed signal in order to determine the actual fan speed in relation to the desired fan speed. The PCM uses the cooling fan speed signal in order to reduce the cooling fan noise and in order to maintain the powertrain cooling requirements. The PCM supplies power and ground to the clutch hall effect sensor of the cooling fan clutch. The hall effect sensor returns a signal pulse through the speed signal circuit in response to the reluctor track, which is located inside the fan clutch. If during operation, the PCM detects a loss of the cooling fan speed signal, DTC P0526 will set.


Do you know how to test electrical circuit's ?

Diagnostic Aids
• An inline connector could cause an intermittent DTC. Ensure to test for poor connections and pin retention at all inline connectors. Refer to system schematics for connectors and locations.
• If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .
• Disconnect the harness connector of the cooling fan clutch from the shroud. Inspect the exposed wires between the harness connector and the tubing.
• Inspect the cooling fan clutch harness in order to ensure that the clutch supply voltage circuit is not shorted to the following circuits:
- The 5-volt reference circuit
- The cooling fan speed signal circuit
- The low reference circuit
• DTC P0526 will set if the engine is started without the drive belt ON.


Connector End View Reference: Cooling System Connector End Views
1
Did you perform the Diagnostic System Check - Vehicle?
--
Go to Step 2
Go to Diagnostic System Check - Vehicle
2
Turn OFF the ignition.
Disconnect the cooling fan clutch harness connector at the shroud.
Connect a jumper wire between each of the following circuits:
• The 5-volt reference circuit
• The cooling fan speed signal circuit
• The low reference circuit
Measure the voltage of the cooling fan speed sensor circuit and a good ground.
Turn ON the ignition, with the engine OFF.
Manually rotate the cooling fan clutch.
Does the voltage change from 0 to 5 volts?
0-5 V
YES - Go to Step 9
NO - Go to Step 3
3
Disconnect the jumper wires.
Measure the voltage between the 5-volt reference circuit and the low reference circuit of the cooling fan clutch.
Is the voltage measurement near than the specified value?
5 V
YES - Go to Step 6
NO - Go to Step 4
4
Turn OFF the ignition.
Probe the low reference circuit of the cooling fan clutch with a test lamp connected to battery positive voltage.
Does the test lamp illuminate?
--
YES - Go to Step 5
NO - Go to Step 8
5
Test the 5-volt reference circuit of the cooling fan clutch for a high resistance, or for an open. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
--
YES - Go to Step 14
NO - Go to Step 6
6
Test the cooling fan speed signal circuit of the cooling fan clutch for a short to ground, for a high resistance, or for an open. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
--
YES - Go to Step 14
NO - Go to Step 7
7
Test the cooling fan speed signal circuit of the cooling fan clutch for a short to voltage. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
--
YES - Go to Step 14
NO - Go to Step 10
8
Test the low reference circuit of the cooling fan clutch for a high resistance or for an open. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
--
YES - Go to Step 14
NO - Go to Step 11
9
Disconnect the jumper wires.
Test the cooling fan speed signal circuit of the cooling fan clutch for an open. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
--
YES - Go to Step 14
NO - Go to Step 11
10
Inspect for a poor connection at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .
Did you find and correct the condition?
--
Go to Step 14
Go to Step 12
11
Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .
Did you find and correct the condition?
--
Go to Step 14
Go to Step 13
12
Replace the cooling fan clutch. Refer to Fan Clutch Replacement .
Did you complete the replacement?
--
Go to Step 14
--
13
Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
--
Go to Step 14
--
14
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running in the DTC.
Does the DTC reset?
--
Go to Step 2
System OK

May 27, 2018 | GMC Cars & Trucks

1 Answer

2006 Chevrolet Trailblazer I6 suddenly began overheating at idle. Parts replaced within the last 2 months: Fan clutch, Tstat, radiator, radiator cap


How about the water pump ? Who replaced the parts ? A qualified repair shop ? Were codes checked ?
The PCM controls the electro-viscous fan clutch engagement. The PCM regulates a 12-volt pulse width modulated signal (PWM) to the cooling fan relay. The PWM signal determines the ON time of the relay. As the commanded state of the fan clutch increases, so does the ON time of the relay. This ON time directly effects the amount of time the solenoid, which is internal to the fan clutch, is energized. When the solenoid in the fan clutch is energized, it opens the spring loaded valve and allows fluid to flow from the storage chamber to the fluid coupling of the cooling fan clutch, increasing the fan speed. When the solenoid is de-energized, the spring loaded valve closes, and blocks the path of the fluid to the fluid coupling of the fan clutch, reducing fan speed.
The fan has the ability to create a feedback signal, so the PCM has an actual fan speed input. This is done with a hall effect sensor internal to the fan clutch. The PCM supplies a 5-volt reference and a low reference to the hall effect sensor. The hall effect sensor returns a signal pulse through the cooling fan speed signal circuit in response to the relucktor track passing by the magnetic field of the hall effect sensor.
Was electrical tested before fan clutch was replaced !

Sep 29, 2016 | 2006 Chevrolet Trailblazer

1 Answer

How do I fix Diagnostic code 351


1. Check for power to the ignition coil when cranking.

2. Check continuity between the Powertrain Control Module (PCM) and the coil on the coil ground circuit wire.

3. Check connections at the coil and at the PCM.

4. If good, replace the ignition coil.

5. If the problem is still there, replace the PCM.

Jun 26, 2012 | 1997 Jeep Grand Cherokee

2 Answers

My 98 cherokee classic sport is overheating when it idles even if it is just a long red light. I have replaced the water pump and flushed the system and replaced the thermostat about 4 months ago. The...


It could be the fan clutch not engaging which will not pull air through the radiator, it may still appear to be spinning but it could not be at the correct RPM for adequate cooling. Hope that helps.

Aug 05, 2011 | 1998 Jeep Cherokee

1 Answer

The fan motor quit working.my sons replaced the cooling fan they hooked up the black wire and yellow wire were they belong but they ran a hot wire from the battery to the green wire. then the wipers and ac...


Step 1 - Remove green wire
Step 2 - Check for blown fuses
Step 3 - Pray the PCM is okay ;)

Adding wires to a car to boost performance in some way, whether to the cooling fan or to the fuel system may have worked 30 years ago, but it seems like the only mechanical thing in a car built after '83 is the engine. Causing power surges, feedback and power draws can and often will do more harm than good. If there's a problem with the cooling fan motor, even after replacement, the motor may never have been the problem. There's the coolant temp sensor, cooling fan relay, PCM..... too many possibilities to just throw parts at.

Let's just look at GM's, for an easy example. In the old days, pulling the positive cable off the battery was a sure-fire way to diagnose an alternator/generator. Nowadays, pulling the positive cable while the engine is running can cause a spike in the charging system so severe, it can fry the PCM. Fry the brain.

We can still service these vehicles at home, but we have to be careful. Where we used to adjust the choke to cure a cold start problem, now it may be the engine temp sensor. It may be the mass airflow sensor. It may by the throttle position sensor, map/baro sensor.....

Let me know what comes from this. Hopefully, no damage was done, and removing the wire and replacing any blown fuses will do the trick. Best of luck!

May 22, 2010 | 1995 Ford Escort

2 Answers

If i hooked a hot wire with a switch up to my dual radiator fans with a switch, would that affect my 1998 dodge neon, 2.0 L, manual transmission, dohc to have a problem dying? I have replaced the cam,...


PCM is difficult to diagnose without proper scan tool, commanding components and verifying pcm ability to control them. Watching data as compared to actual inputs, these eliminate all but the pcm. As for the cooling fans, I have seen cooling fan related issues cause the pcm to failsafe. Causing stalling, low power, and rough idle. Why did you install a manual switch. If pcm is commanding them on and the fans, relays, and circuits are good then your circuits are good. I would look into why the fans are not operational and this may lead to the diagnosis you need.

Sep 09, 2009 | 1998 Dodge Neon

1 Answer

Fan still doesn't work.


You may want to trace that relay power wire back. There may be a fuse under the dash that supplies power to it, and likely another in the distribution center. I'm fairly sure the pcm supplies the ground signal to the relay.

Jul 25, 2009 | 2001 Jeep Grand Cherokee

1 Answer

Overheating engin when at idel, fan not working


does both the hoses get hot bottom and top? this will tell you if theres flow through the radiator. If you have a voltage tester test the wires on the fan connecter check there is current going to the fan if so replace the fan its a common problem as previously stated. 
if there is no power to the fan when the vehicle should be turning it on i.e. its hot enough check the fan relay under the hood.

Nov 23, 2008 | 1999 Jeep Grand Cherokee

Not finding what you are looking for?
1999 Jeep Grand Cherokee Logo

81 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jeep Experts

yadayada
yadayada

Level 3 Expert

80339 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Kevin Daniels

Level 3 Expert

1455 Answers

Are you a Jeep Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...