A/C blows on High Mode Only

Hi Speed A/C Blower Only For Jeep Cherokee

Q: Suddenly, Air condition will only work on the HI setting on my 1995 Jeep Grand Cherokee. If  set  to any other setting, no air will blow out. This sounds like an electrical problem but I’m not sure. Any ideas?

A: A very common problem.Your Jeep may be in need of a blower resistor. When you turn the blower speed control you’re directing electricity though different paths, all of which go to the blower motor. When you select low speed through mid speed you are really directing the electricity through a part called a resistor block. The resistor block has different resistors that control the amount of electricity that goes to the blower motor. But why only high speed? When the blower speed selected is high the resistor block is by-passed and full electrical power is directed straight to the blower motor. In most cases all that is needed is a new blower resistor block to return blower speed control.

Vehicle Stalls At Idle

Jeep Wrangler, Stalling Problems Troubleshooting

Q: Its a Jeep Wrangler 4.0L with an automatic transmission.

The Problem Noticed is :------ At cold start up it revs to fast idle then as it comes down to regular idle it stalls out. Restarting it may or may not stall again. When it reaches operating temperature, it runs fine.

Parts Replaced :----  The plugs, ignition wires, rotor and distributor cap were replaced at 2k-2.5k miles before stalling started and they still look good. Fuel pump pressure is normal. This vehicle has 143k mile on it and has given excellent service.

A: Take the air inlet hose off where it enters the throttle body and take a look at the throttle plates. It is likely that they’re dirty and have a build-up of carbon deposits. That is the most common cause for stalling that we see in the shop for your vehicle. Sometimes all it takes is a good cleaning to cure the stalling problem. There is an idle speed setting on your Jeep, but to check and/or perform this service step requires the use of a computer scan tool for your vehicle. If the cleaning doesn’t help ask a repair facility to check and reset, if needed, the minimum idle speed on your Jeep.

Ignition Coils Burning

Jeep Grand Cherokee Ignition Coil Burns Again n Again



Q: For Jeep Grand Cherokee. Idling very slow. I replaced the plugs wires and fuel filter but, still idled slow. I sent it to a mechanic who replaced the ignition coil and distributor pick up and it ran fine for one day. I took it to work and when I went to leave it wouldn’t start. I checked it and there was no spark so I took it back to the mechanic and he said the new coil went bad. He replaced it and it ran for 2 days then I went to drive it home from work and it wouldn’t start. I purchased another coil myself installed it and it fired right up. Do you have any idea why it’s burning up the coils?


A: Before replacing the coil too many more times you may want to go the Jeep dealer and buy an updated ignition coil and harness. The ignition coils were known for shorting internally, causing a variety of running problems. The update called for a lower internal resistance coil and a modification to the wiring harness that included an external resistor. If you’re installing an aftermarket coil that has a lower internal resistance without the wiring harness modification you’ll just keep burning out ignition coils.

Technical Service Bulletin Recalls For Jeep Cherokee

Safety Recalls For Jeep Cherokee

Q: Need listing of the recalls (safety and other) for  1994 Jeep Grand Cherokee. Can you help me find this list? All I am able to find are some safety recalls and next to no Service Bulletins.

A: Any person can check on safety recalls by calling the National Highway Traffic Safety Administration at 888-327-4236 or at www.nhtsa.dot.gov. As for TSB’s (Technical Service Bulletins) that is a different story. First you have to understand that a TSB involves a problem. The first problem with a problem is its definition. In the Webster’s big book a problem is defined as 1. a question proposed for solution or consideration. 2. a question, matter situation, or person that is perplexing or difficult. 3. in mathematics (hey this doesn’t count here forget it, need the space) The problem is there is no #4. who pays to fix the problem? Is it the tech? No, he/she works for the dealership. After all you can’t feed a family or own a house if you don’t get paid. The dealership? Yea at first they’re stuck with the cost until they get the money out of the folks who designed and built the vehicle. Of course the first thing they say is there’s no problem- must be your techs. Once enough dealerships are screaming, (just like their customers) the maker realizes Oh, maybe there is a problem. In the interim the solution, or an in the field fix is found. Here’s where the cost of a TSB really jumps. The maker has to get this information out to all the other dealerships, to let their techs know how to fix the problem, which may include redesigned parts. Also if the car is new enough the repairs may be for free (eegkads!). Getting the TSB out to all the dealers and techs, not to mention any parts, costs big bucks. Loss of big bucks means loss of big bucks! There are research and development costs, warehousing, distribution costs, transportation & delivery costs, installation costs, not to mention the white shirts trying to justify their corporate existence, it just plain cost money! Then a person like you or me comes along and asks for this information for free? Right! Hey they got the investment and need a return. Even the folks at ALLDATA Information Systems  have to pay for the information and the right to reprint it. Whether it’s computers, medicine, law or cars information is not free. Someone (that is you or me) has to pay for information in its final form.

Vehicle Will Not Start After Replacing Transmission

 No Start After Transmission Replaced

No Starting Issues & Transmission Problems


Q: Dropped  transmission on Jeep Cherokee to replace the oil seals that were leaking badly. After put it back in and now it won't start. Do I have to re-calibrate the computer or something? Any help would be awesome.



A: If it cranks over good but will not run I’d be looking at the crankshaft position sensor. The crankshaft position sensor is mounted in the bell housing of the transmission. The sensor is mainly plastic with very, very small wires inside. If it is hit, the engine is a no go. The quickest test is with a scan tool. With the scan tool connected to the computer go the crankshaft signal screen and crank the engine over. The computer will say yes for a crankshaft signal and no if there is not one. If no signal, a replacement sensor is likely needed.

Engine Quits After Running Few minutes

Engine Dies After Driving Few Minutes

Q: The engine just quits on  Jeep Cherokee after driving for few  min. Already replaced the fuel filter, spark plugs & wires and the distributor cap....What else can I check?


A: First, you're not checking you're replacing parts. This is a costly way to approach a problem. If the problem is so persistent you should be able to time a drive to a repair facility for diagnosis. But then again if it is anything like what happens when a problem vehicle comes to our shop, the problem goes away. You know the dentist and the tooth ache scenario? It is unlikely that the parts or related parts to the items you've replaced are the cause for your engine just shutting down. With Jeeps I'm more inclined to inspect critical inputs to the computer. Component failures that I have seen that are heat related on Jeeps have been the crankshaft position sensor. When this sensor drops out (fails) the computer just stops doing about anything. The signal from this sensor is a critical input and without it the vehicle will not run. Why? The signal from the crankshaft position sensor allows the computer to know when to provide spark and fuel. The Jeep just becomes a boat anchor until the signal returns. A problem as persistent as you're describing should be easily diagnosed. Once you have the diagnosis and know what has to be replaced life gets simpler.

Vehicle Quits While Driving

Engine Goes Dead While driving

Q:  Jeep Cherokee runs well 99.9% of the time. However, sometimes when driving, it will go dead. Usually it cranks right up when I pull to the shoulder of the road. Sometimes it will run for days with no problems. Other times it goes dead two or three times a day. I had it in the shop for a week, but they could not find anything wrong with it. Any suggestions?

A: If your Jeep is shutting off like someone turned the key I would be critical of the crankshaft position sensor. While your Jeep is running you can unplug just about every computer sensor on the engine and it will still run, not great but run. If the signal from the crankshaft position sensor is lost on your Jeep, the curtain drops like a rock on that show. The fuel injectors, along with the ignition system, are shut right down. Just bang, end of show! While the crankshaft position sensor is off line from the rest of the vehicle, you can crank the engine over until the battery goes dead or the starter burns up, it's just not going to start. The next time this condition occurs on your Jeep, turn the ignition off and then cycle the ignition from off to on three times. On the third cycle leave the ignition in the on position. At this point watch the check engine light it should start to flash. If the code flashed is an 11 it is a good bet that the crankshaft position sensor has failed. So, the next time your Jeep drops dead, cycle the key and find out what the computer might have to share with you while you wait.