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Possible to add a manual switch for aux cooling fan on 96 XJ?
I would like to add a manual on off switch (maybe 3 way switch) to let me manually turn on the electric aux cooling fan. Is there such a thing or would I need to install an aftermarket electric fan?
The temperature on the thermostat housing never gets over 205, so the fan never comes on unless I turn on the A/C. I have replaced the rear temp sensor for the gauge, the thermostat, thermostat housing and sensor, fan clutch, idler pulley and belt, upper and lower radiator hoses and the gauge on the dash is above 210 and below the next white line (240?). I checked the thermostat's housing temp and rear sensor temp with a Fluke IR temp gun and they both show under 200. When I replaced all the parts, I did not notice any crud in the cooling system, so I do not think there is any build up in there. If I turn on the A/C the temp goes down closer to 210. I am not sure if it is a original radiator, it looks newer than the rest of the parts. Maybe its the relay? The fan does turn on as soon as I turn on the A/C.
Should I take it to a radiator shop and have them flush it? I live in a condo and doing a full flush here is not an option.
The dash gauges can be inaccurate as far as numbers are concerned. Is this the temp it always drives at?
I use the IR temp gun also have more trust in them than the gauge.
There is an easy way to trigger the aux fan. It involves grounding one wire, through a switch in dash. Computer still retains full function of fan also. Only downside is, when used it will trigger a CEL.
Will have to find the write-up for that..
So I should not worry about what the dash temp gauge says? Is it possible to replace just the temp gauge?
Originally Posted by SteveMongr
The dash gauges can be inaccurate as far as numbers are concerned. Is this the temp it always drives at?
I use the IR temp gun also have more trust in them than the gauge.
There is an easy way to trigger the aux fan. It involves grounding one wire, through a switch in dash. Computer still retains full function of fan also. Only downside is, when used it will trigger a CEL.
Will have to find the write-up for that..
Mine does literally exactly the same thing. I've been meaning to replace the gauge for a while. For a while I was going crazy too and replaced the entire cooling system with better than stock parts, pulled the head had it surfaced, new head gasket, new sensors etc. Finally checked it one day with a calibrated IR gun and found my temps actually were not what the gauge was saying.
However if you're still interested in adding a switch for the fan this is the way to do it (doesn't trip my CEL):
This is technically how to wire aftermarket electric fans but the concept is the same. The switch will control the fan when you want it switched on and the computer will still switch the fan on if the AC is turned on or the engine gets too warm. Credit to whomever I borrowed this picture from.. I don't remember.
Does the switch go on the green wire? Is that a stock relay it is referencing? Where exactly did you point the IR temp gun at to get your temps?
Originally Posted by vank
Mine does literally exactly the same thing. I've been meaning to replace the gauge for a while. For a while I was going crazy too and replaced the entire cooling system with better than stock parts, pulled the head had it surfaced, new head gasket, new sensors etc. Finally checked it one day with a calibrated IR gun and found my temps actually were not what the gauge was saying.
However if you're still interested in adding a switch for the fan this is the way to do it (doesn't trip my CEL):
This is technically how to wire aftermarket electric fans but the concept is the same. The switch will control the fan when you want it switched on and the computer will still switch the fan on if the AC is turned on or the engine gets too warm. Credit to whomever I borrowed this picture from.. I don't remember.
Does the switch go on the green wire? Is that a stock relay it is referencing? Where exactly did you point the IR temp gun at to get your temps?
Green wire is the one that comes from the stock aux fan plug. That relay is one you would add to the system so that you aren't running direct battery power through the switch. I pointed the IR gun at the thermostat housing, sensor at the back of the head, really anywhere on the head just to make sure the temps aren't as crazy as the gauge says. Just remember most IR guns have an emissivity setting and you need to set it for the material you're shooting to get a proper reading.
"But i wanted to do my own write up. I did it on my 94 and it only works on 91-95's as far as i know. Newer ones will throw a CEL and older ones are run differently."
"But i wanted to do my own write up. I did it on my 94 and it only works on 91-95's as far as i know. Newer ones will throw a CEL and older ones are run differently."
Mine is a 96, so this will not work on mine?
That link shows how I did it on my '96. But I did not have to bust open the wire harness that much and did not use one of those crappy 3-way connectors. But the idea is the same. Same wire color.
Will trigger a CEL that has to do with coolant temperature sensor. Here in NC inspections have nothing to do with codes or CEL. But could cause an issue elsewhere.
I wasn't sure what years that write up was compatible with, but good to know 'cause Colo. won't pass emissions with the cell light on. Mine is a 91' so I should be ok doing it that way right?
Colorado will pass you with a CEL on. I was under the same impression until recently I sold a car and had emissions done for the buyer. Apparently the CEL was burned out but there were two codes thrown that the test facility read and printed on the emissions form as informational only. The car passed anyway. I talked to the gal running the test and she said all CO cares about now is the actual emissions levels. If you're below these levels then you pass regardless of CEL. This was in January.
There is also the V8 Grand Cherokee fan clutch that is a direct replacement for the XJ.
It moves more air, good for slow speed/higher rpm driving, like sand. Also helps the AC in summer. Jeep can idle with AC on and will not heat up. The sacrifice is a loss of about 1 mpg, and more fan noise.
These fan modifications are only for adverse driving conditions. Not to help a poorly operating cooling system.
I might be removing my a/c for more space in front of the radiator. for a P/S cooler and better air flow through the radiator.
I removed the AC condenser in my '91 for the same reason, more airflow. I was advised by an old timer to place a piece of metal window screen behind grill, to protect radiator from bugs,debris,rocks.
Compared to the AC condenser, the radiator metal is soft and easily damaged. Window screen worked well.
03-04-2015, 12:44 PM
Possible to add a manual switch for aux cooling fan on 96 XJ?
