Dragon158
06-23-2014, 05:28 PM
Ok, I know... but I haven't been able to find the info I'm looking for, what I'm looking for is an explanation of how my system works. I'm new to Cherokees and this is the first time I'm seeing this dual pressure cut off switch mounted to the line on my 2000. I understand that this setup was only used on 2000 & 2001 models.
First a little history, I had a small overheating issue last summer. Thermostat was shot, replaced and all was cool. Then the a/c compressor locked, or just about locked up. I swapped a new one, all was cool again. Towards the end of last summer I saw a puff of steam and traced it to a small pin hole in my radiator. Swapped in a new one, all was cool once again. This fall I noticed my reservoir was empty and found a leak at the weep hole on the water pump, swapped a new one and I was cool, again. Well this passed friday I was in heavy stop and go city traffic, with the a/c cranked and the temp around 90 degrees. I hear the chime and see the warning light to check gauges. The temp was up to 230 / 235. I pull over, pop the hood and see the electric fan is out. I continue driving home, with a/c off and had no more overheat issue. When I get home I start diagnosing the issue, jump the fan, check the fuses... then I see this switch. I google a bit and find somewhere someone says to ground the switch, if the fan works when grounding it's a bad switch. I order the switch from the dealer, install it today and still no worky. I have access to Chrysler and started digging through wiring diagrams and want to see how this system works, since throwing money at it doesn't seem to work. I find a diagram that says the pcm supplies ground to the circuit to turn the fan on & my pcm doesn't appear to be doing that, I ran a jumper to ground and the fan worked. So now I'm looking at an expensive pcm. Now onto what may turn into a bunch questions, where does the temp side of the system come in? Obviously that isn't working either. As far as I can tell the electric fan doesn't work with the a/c on or the temp going to overheat. I have access, but can't navigate Chrysler very well & find diagrams for circuits is a bear, probably because I'm still used to books. So in closing if anyone has any idea how this system works, or has been down this road PLEASE chime in. Like I said, this system is new to me & I can't throw a $500.00 PCM at it. But I may throw a toggle switch at it...
Thanks in advance, sorry it's sooo long. - Shawn
First a little history, I had a small overheating issue last summer. Thermostat was shot, replaced and all was cool. Then the a/c compressor locked, or just about locked up. I swapped a new one, all was cool again. Towards the end of last summer I saw a puff of steam and traced it to a small pin hole in my radiator. Swapped in a new one, all was cool once again. This fall I noticed my reservoir was empty and found a leak at the weep hole on the water pump, swapped a new one and I was cool, again. Well this passed friday I was in heavy stop and go city traffic, with the a/c cranked and the temp around 90 degrees. I hear the chime and see the warning light to check gauges. The temp was up to 230 / 235. I pull over, pop the hood and see the electric fan is out. I continue driving home, with a/c off and had no more overheat issue. When I get home I start diagnosing the issue, jump the fan, check the fuses... then I see this switch. I google a bit and find somewhere someone says to ground the switch, if the fan works when grounding it's a bad switch. I order the switch from the dealer, install it today and still no worky. I have access to Chrysler and started digging through wiring diagrams and want to see how this system works, since throwing money at it doesn't seem to work. I find a diagram that says the pcm supplies ground to the circuit to turn the fan on & my pcm doesn't appear to be doing that, I ran a jumper to ground and the fan worked. So now I'm looking at an expensive pcm. Now onto what may turn into a bunch questions, where does the temp side of the system come in? Obviously that isn't working either. As far as I can tell the electric fan doesn't work with the a/c on or the temp going to overheat. I have access, but can't navigate Chrysler very well & find diagrams for circuits is a bear, probably because I'm still used to books. So in closing if anyone has any idea how this system works, or has been down this road PLEASE chime in. Like I said, this system is new to me & I can't throw a $500.00 PCM at it. But I may throw a toggle switch at it...
Thanks in advance, sorry it's sooo long. - Shawn