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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
i always like your good explenations and what you mentioned does make sense to me, thats something i didnt think of a false gauge reading. sure an interesting thing and something to check out, thank you for your input
second thought on this i dont know if it means something but when i start the jeep the temperature guage goes all the way to maximum until the engine runs and moves back to the left side and starts to tell the temperature, i always wondered if this is normal ?
Note from DJ
Just my thoughts on your problem for what it’s worth.
First of all I think that your concern over the fact that you are unable to get your Electric Fan to come on when you select the AC mode is never going to happen.
Here is my reason why; when you select the AC mode the AC Clutch Relay located in the PDC is supposed to close and engage the AC Compressor clutch; which cause the AC Compressor to start the cooling process and energize the Electric Fan at the same time to aide in the condensing of the refrigerant. But there is a low pressure switch in this circuit that is probably not closed because the system is too low on refrigerant therefor it is saying no can do. That’s why the Electric Fan is not coming on in the AC mode.
Now on to the real your problem at the moment is your concern over the fact the Electric Fan is not coming on at higher temperature readings of the DASH TEMPERATURE GAGE. The fact the Electric Fan doesn’t work in AC mode has no effect over this problem.
So on to my thoughts on this concern.
On Jeeps there are two coolant sensors. There is one at the front of the engine in the thermostat housing, this one has two wires. The two wire sensor located in the thermostat housing sends its signal to the PCM for performance issues.
Then there is another at the back drivers topside of the engine cylinder head just to the right of the valve cover, this one has one wire. THE ONE WIRE SENSOR IN THE BACK SENDS TEMP READINGS TO THE GAUGE IN THE JEEPS DASH. If you temp gauge isn't acting right, this may be where your problem is and may need replacement. These too different sensors work independent of each other.
So the Dash Gage may be showing a much higher false temperature reading then the front sensor is seeing; which is the sensor that if needed will send out the signal we need extra coolant help and turn on the Electric Fan.
Photo of Dash Gage Sensor
Temp Sender Switch Temp Rating: At 100 Deg. F. 1320 Ohms With 2% Tol, At 220 Deg. F. 1250 Ohms With 2% Tol
Temperature Switch Thread Size: 1/8 x 27 in.
1994 will have both. Cooling fan relay might be by air filter box drivers side fender.
You can jump the low pressure switch of ac by jumping its plug with a paper clip while engines running ac on.Its on passenger side by heater hoses and oil dip stick area. You only do this for a second.
this socket/connector is on the drivers side fender wall is still a mistery to me where that goes or what plugs into it.
this socket/connector is exactly on the same spot where other models have the fan relay but this socket doesnt look like it would hold a relay, not sure if this is for a more deluxe version
i found the low pressure switch and used a paper clip on the plug while the engine is running, i dont hear anything engaging or clicking near the air conditioner compressor.
so i had a better look at the front of the compressor like in the video you showed.
the metal ring/plate that should spin seems very loss compare the pictures both one with the plate pushed up and on the other picture the plate pushed down, i might be wrong but that seems like a lot of play is it broke ?
Note from DJ
I edited my Post #30 on the 16th this higher water temperature value should have been 125 ohms not 1250 ohms
Coolant Temperature Gage Operation
The Coolant Temperature Gage Sensor at the back side of the Head below the Valve Cover next to the Master Cylinder is a variable resistor. It has a low resistance when the coolant is hot and a high resistance when the coolant is cool.
Simple test of gage or sensor malfunction:
Gage Test: Turn key to the on or run position and unplug connector from sensor, gage should show lowest temperature reading. Now ground the sensors connector to a good ground and gage should now show maximum temperature. If both tests pass testing the wiring and gage are OK.
Sensor Test: Take a VOM meter set to ohms scale and take the negative lead and attach it to a good ground; take the positive lead and attach it to the pin at the top of the sensor, depending on the temperature hot or cold look for Approximate Ohms Value below.
EXAMPLES OF APPROXIMATE VALUES:
100F=1360 ohms
220F=125 ohms
Regarding your question in post #32 regarding the temperature gauge orientation on startup; yours is backwards to my 88 mine starts at low temperature.
Regarding your question in post #36 about the mastery connector?
If my information is correct the wire colors connected to that connector are as follows:
1. Is Black with White tracer
3. Is Pink
4. Is Light Green
5. Is Dark Blue with White tracer this connection will show battery voltage in the start or run position of the ignition switch.
If your mystery connector meats these qualifications it is probably the Diagnostic Connector.
i found the low pressure switch and used a paper clip on the plug while the engine is running, i dont hear anything engaging or clicking near the air conditioner compressor.
so i had a better look at the front of the compressor like in the video you showed.
the metal ring/plate that should spin seems very loss compare the pictures both one with the plate pushed up and on the other picture the plate pushed down, i might be wrong but that seems like a lot of play is it broke ?
Seems somethings not right if theres movement.Looks like clutch is blown on compresure. I gather fan did not kick in when jumped. Any way to post a video of movement?
this socket/connector is on the drivers side fender wall is still a mistery to me where that goes or what plugs into it.
this socket/connector is exactly on the same spot where other models have the fan relay but this socket doesnt look like it would hold a relay, not sure if this is for a more deluxe version
Have you ever checked codes ?Disconnect battery negative cable for 15 minutes then reconnect and let jeep get to operating temp. Get a pen and paper and do this.....
indeed the wiring color on the mystery connector is exactly right as djgrayxj stated and correct with the voltage aswell. thanks so much for clearing this up a Diagnostic Connector.
after jumping the low pressure switch for the air conditioning as i forgot to mention the auxiliary fan did not come on.. nothing happened at all
the temperature gauge test worked good too, when the single wire connector is unplugged there is no movement at all really just stays on 100F and when grounding the single wire connector indeed the gauge needle shoots all the way to the right way passed the 260F.
i didnt get to the sensor test itself yet cause what do ya know im out of gas lol so i couldnt warm it up to 220F but thats alright will do this tomorrow
05-16-2017, 12:06 AM
