95 XJ cooling fan problem

[DaveB]

I have been out trying to figure out why my son in law's 95 XJ is overheating going up hills. What I found was that his fan clutch was bad and I swapped that which helped but the main problem is that his secondary electric fan isn't turning on. The electric cooling fan is enabled by the computer when it senses that the engine is too warm or whenever the AC is turned on. The computer is able to sense that the AC is on and will turn the fan on so I know the fan and fan relay are good. I have also checked the interconnect between the computer, relay and temp sensor and the connections are all good. The temp sensor is also measuring the correct resistance measured at the computer connector. The interresting thing is that when it gets too warm I can kick on the AC for a second then back off and the fan will now stay on until the temp drops to the normal range. It appears to me that the problem is in the computer itself where it can sense the temp but can't turn the fan on. So I will need to find him a new computer. I have computers from a 91 and a 92 and I can't see why it would'nt work to swap them in but they have different part numbers. Does anyone know why the part numbers are different for the 91-95 years which have the same sensors etc ?

 

[Badger]

its most likely the temp gauge itself at the thermostat housing.we got into this conversation with Bretts thread.i thought the same thing about it going back to the computer but it would seem that it doesn't.

 

[DaveB]

its most likely the temp gauge itself at the thermostat housing.we got into this conversation with Bretts thread.i thought the same thing about it going back to the computer but it would seem that it doesn't.

I did swap out his temp sensor becuse it was reading a bit too high but the replacement one does the same thing. Maybe I'll try another one. The sensor seems to be doing the right thing once I turn the fan on by toggling the AC on and off.

 

[Badger]

if you have some spare computers you could try changing them out.the parts numbers shouldn't make a difference.as long as they are from the same thing you have they will work.if you have an auto then you need a computer from an auto .if you have a manual then you need one from a manual.if tis from a 91 to 96 it will work.

 

[DaveB]

if you have some spare computers you could try changing them out.the parts numbers shouldn't make a difference.as long as they are from the same thing you have they will work.if you have an auto then you need a computer from an auto .if you have a manual then you need one from a manual.if tis from a 91 to 96 it will work.

The 91 and 92 were for autos so they should work. I may even test it by manually changing the sensor resistance once the engine is warm to see if I can force it to turn on.

 

[waynehartwig]

Fed and CA emission is also a different computer....

 

[Devel]

if you have some spare computers you could try changing them out.the parts numbers shouldn't make a difference.as long as they are from the same thing you have they will work.if you have an auto then you need a computer from an auto .if you have a manual then you need one from a manual.if tis from a 91 to 96 it will work.

Dont u mean 91 to 95? 96 is an OBD2 computer where the 91 to 95 is an OBD1 Computer

 

[Badger]

yes 95 sorry i usually just go by the body change but yes the OBDII was really started in 96.i wouldn't doubt if some of the early 96's still had OBDI that were left over.