Jrclark
New Member
- First Name
- Jason
- Joined
- Jul 19, 2019
- Threads
- 1
- Messages
- 1
- Reaction score
- 4
- Location
- Wyandotte, MI
- Vehicle(s)
- 2019 JLU Sport 3.6L
- Occupation
- Battery Systems Engineer
- Thread starter
- #1
Hey everyone! I have some information to share regarding a radiator fan not working. Maybe this can help others.
2019 JLU 3.6L with 1880 miles. I notice the check engine light came on. I then noticed the AC air was hot while at a red light and sitting in a parking lot. I realized the coolant temperature was rapidly rising. I assumed the radiator fan was not on, as the coolant temp stayed steady while driving, and the AC air would be cold as well. It got enough air across the radiator while driving to keep it stable. I am leasing the Jeep so I called the dealer to get it in immediately. The service employee I met with used an OBD scanner and confirmed he was getting an error code for the radiator fan not getting power. This happened on a Friday afternoon, and he told me he could not have anyone look at it until Monday morning and the radiator fans were on back order for 10 days! He also stated there were no available rental vehicles. I called around to other local dealers and they all had the same story. Great customer service for a BRAND NEW Jeep that was overheating.
I drove my Jeep home and kept a close eye on the temperature, let the start/stop feature do it's thing at lights to keep the temp down. Made it home safely. I decided to check out the fuse box myself, and I learned there is a fuse link cable between the fuse box (TIPM?) and the radiator harness. It started to POUR and I mean POUR so I quickly closed the hood and went inside frustrated. I called it a night and stayed home.
Fast forward to Saturday morning I was determined to see what was going on and was not going to chalk it up as a bad radiator fan assembly. I unplugged the connector on the harness to the radiator fan, and used a DMM to check for continuity between the positive pin (red wire) to the terminal at the fuse box, as well as the ground (black wire) to the battery ground. Both had continuity. I also measured resistance at these points, and it showed 0.4 ohms which honestly seemed high to me. But regular old DMMs are not accurate for low resistances, you need a milli or micro ohm meter. I tried to measure voltage with the car on, and got nothing (maybe it didn't try to kick the fan on yet?).
Then I realized something; I noticed the bus bar on the cable didn't seem flush to the terminal on the fuse box, like the rest were. THE NUT WAS LOOSE. I grabbed a 10mm and tightened it up (with the car off). Turned the car on, blasted my AC and the sweet sweet loud sound of the radiator fan was like music to my ears. Let the car sit, and the coolant temp was staying at a steady 194F. Took it for a quick drive to test it out, and it was working perfect, doing its job to keep the coolant temp at 194. Seems like the loose nut was preventing the bus bar on the cable from making good contact with the fuse box terminal. This can be dangerous because if a terminal is not torqued properly it increases resistance and will generate heat and can even lead to a fire! I'm an electrical engineer in automotive I need to know these things haha.
I plan to take it to my dealer appointment I had made for Monday morning and telling them what happened. I need them to clear the error code for the check engine light to go away. I want them to be aware of this in case other JLs come in with the same problem. Possibly get someone to check out the assembly line if this is a common problem. If anyone having an issue with overheating, or radiator fan not working, I hope this post helps you. Check the bolt.
TL;DR: Radiator fan wasn't working. The nut on the fuse box for the radiator fan fuse like cable was loose, it wasn't getting contact.
2019 JLU 3.6L with 1880 miles. I notice the check engine light came on. I then noticed the AC air was hot while at a red light and sitting in a parking lot. I realized the coolant temperature was rapidly rising. I assumed the radiator fan was not on, as the coolant temp stayed steady while driving, and the AC air would be cold as well. It got enough air across the radiator while driving to keep it stable. I am leasing the Jeep so I called the dealer to get it in immediately. The service employee I met with used an OBD scanner and confirmed he was getting an error code for the radiator fan not getting power. This happened on a Friday afternoon, and he told me he could not have anyone look at it until Monday morning and the radiator fans were on back order for 10 days! He also stated there were no available rental vehicles. I called around to other local dealers and they all had the same story. Great customer service for a BRAND NEW Jeep that was overheating.
I drove my Jeep home and kept a close eye on the temperature, let the start/stop feature do it's thing at lights to keep the temp down. Made it home safely. I decided to check out the fuse box myself, and I learned there is a fuse link cable between the fuse box (TIPM?) and the radiator harness. It started to POUR and I mean POUR so I quickly closed the hood and went inside frustrated. I called it a night and stayed home.
Fast forward to Saturday morning I was determined to see what was going on and was not going to chalk it up as a bad radiator fan assembly. I unplugged the connector on the harness to the radiator fan, and used a DMM to check for continuity between the positive pin (red wire) to the terminal at the fuse box, as well as the ground (black wire) to the battery ground. Both had continuity. I also measured resistance at these points, and it showed 0.4 ohms which honestly seemed high to me. But regular old DMMs are not accurate for low resistances, you need a milli or micro ohm meter. I tried to measure voltage with the car on, and got nothing (maybe it didn't try to kick the fan on yet?).
Then I realized something; I noticed the bus bar on the cable didn't seem flush to the terminal on the fuse box, like the rest were. THE NUT WAS LOOSE. I grabbed a 10mm and tightened it up (with the car off). Turned the car on, blasted my AC and the sweet sweet loud sound of the radiator fan was like music to my ears. Let the car sit, and the coolant temp was staying at a steady 194F. Took it for a quick drive to test it out, and it was working perfect, doing its job to keep the coolant temp at 194. Seems like the loose nut was preventing the bus bar on the cable from making good contact with the fuse box terminal. This can be dangerous because if a terminal is not torqued properly it increases resistance and will generate heat and can even lead to a fire! I'm an electrical engineer in automotive I need to know these things haha.
I plan to take it to my dealer appointment I had made for Monday morning and telling them what happened. I need them to clear the error code for the check engine light to go away. I want them to be aware of this in case other JLs come in with the same problem. Possibly get someone to check out the assembly line if this is a common problem. If anyone having an issue with overheating, or radiator fan not working, I hope this post helps you. Check the bolt.
TL;DR: Radiator fan wasn't working. The nut on the fuse box for the radiator fan fuse like cable was loose, it wasn't getting contact.
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