Go Back   Infamous Nissan - Hardbody / Frontier Forums > Tech Area > Wiring and Electrical

Reply
 
Thread Tools Display Modes
Old 08-07-2020, 05:29 PM   #1
joboy77
 
joboy77's Avatar
 
Join Date: Nov 2017
Location: Surprise, AZ
Posts: 51
Vehicle: 1997 Hardbody
Thanks: 16
Thanked 11 Times in 9 Posts
Default Thermal switch/Anti Ice switch

Hey all, I've been chasing down problems with my a/c (summer in AZ it totally sucks driving with out)for a while and after fixing leaks and changing some parts I think maybe the thermal switch or anti ice switch or whatever you call it may be bad. The one on top of the evap box that has a little sensor shoved into the fins of the evaporator. I've looked up the part and it's fairly expensive $120. How often do these go bad? Is it a common thing? I did a search but not too many threads come up about these going bad. Thanks
joboy77 is offline   Reply With Quote
Old 08-10-2020, 01:00 AM   #2
david29
Administrator
 
Join Date: Sep 2008
Location: Spring(Houston), Texas
Age: 50
Posts: 6,121
Vehicle: 1987 Nissan King Cab
Thanks: 28
Thanked 539 Times in 482 Posts
Default

I’ve never replaced one on any of the trucks I’ve had. But I have sold a few from parts trucks I torn apart over the years.
__________________
My stable of Nissan trucks includes:
1987 Nissan King Cab(full frame off Restoration).
david29 is offline   Reply With Quote
Thanked by:
joboy77 (08-10-2020)
Old 08-10-2020, 02:41 PM   #3
Cusser
 
Cusser's Avatar
 
Join Date: Aug 2016
Location: Hot Arizona
Posts: 546
Vehicle: 2004 Frontier
Thanks: 0
Thanked 76 Times in 67 Posts
Default

1. These switches typically have 2 terminals and "open" when temperature approaches freezing, then "close" the circuit once it warms to about 38F.


2. To test the switch, connect the two wires from the switch together (bypassing the switch) and drive for a few days so the circuit will always be completed. If that helps, likely a bad switch. In our temperatures and humidity, doubt that there will be sufficient moisture on the evaporator coils to freeze. And if you are lucky enough to feel "too cold" at times, simply switch off the AC button on the dash.


If the part tests out bad, there may be a universal de-icer switch available that would work.
__________________
2004 Frontier King Cab (2WD, 5-speed, 4-cylinder, 98.5K), 1998 Frontier regular cab (2WD, 5-speed, 4-cylinder 225K), 1988 Mazda B2200 (2WD, 5-speed, 4-cylinder, 214K), 1971 VW Convertible (140K), 2005 Yukon (180K), 1970 VW (260+K)
Cusser is offline   Reply With Quote
Old 08-10-2020, 08:32 PM   #4
cadillacdude1975
The Gear Jammer
 
cadillacdude1975's Avatar
 
Join Date: Apr 2013
Location: Chattanooga, TN
Age: 48
Posts: 9,980
Vehicle: 87 D21 SE KC V6 2wd 5sp & 87 Pathfinder 4x4 SE
Thanks: 396
Thanked 1,208 Times in 1,110 Posts
Default

I believe i have an extra one. Just let me know and i will double check.
cadillacdude1975 is offline   Reply With Quote
Old 08-11-2020, 04:16 AM   #5
joboy77
 
joboy77's Avatar
 
Join Date: Nov 2017
Location: Surprise, AZ
Posts: 51
Vehicle: 1997 Hardbody
Thanks: 16
Thanked 11 Times in 9 Posts
Default

Thanks, but I already bought a new one. My a/c is working at the moment but it goes through periods where it stops working and then for no reason starts again. After I put this part in, the compressor will be the only part I haven't replaced. Lol! I know throwing parts at a problem isn't the best solution, but the parts are cheap and it's friggin hot as you know.
joboy77 is offline   Reply With Quote
Old 08-11-2020, 02:43 PM   #6
Cusser
 
Cusser's Avatar
 
Join Date: Aug 2016
Location: Hot Arizona
Posts: 546
Vehicle: 2004 Frontier
Thanks: 0
Thanked 76 Times in 67 Posts
Default

Quote:
Originally Posted by joboy77 View Post
My a/c is working at the moment but it goes through periods where it stops working and then for no reason starts again. After I put this part in, the compressor will be the only part I haven't replaced. Lol! I know throwing parts at a problem isn't the best solution, but the parts are cheap and it's friggin hot as you know.

Joboy - since you suspected the de-icer switch, I'm guessing that you have visually determined that the compressor is periodically disengaging. That means that the center drive plate of the compressor stops turning, only the outer pulley turns. When that happens, either the AC clutch is not getting 12 volts positive or the AC clutch is slipping.



If that's what's happening, the best way is to determine if the AC clutch is getting 12 volts positive is to check that wire; on my 1998 Frontier I actually stripped back some insulation and soldered-on a wire so I could test with a voltmeter or test light.


So in summer 2019, when my 1998 had this issue, I was able to determine that my AC clutch WAS getting power, but its electromagnet was not engaging the compressor drive plate; that's called clutch slippage, from the gap wearing too large over time. Some check this when the AC clutch disengages by tapping (careful, engine running, belts, etc. - dangerous) the drive plate with a broom handle to see if that causes the drive plate to engage/lock.


In my instance (summer 2019) I removed my AC clutch drive plate and removed a thin shim to narrow the clutch gap, and it's worked fine since. I did NOT have to remove the AC belt or compressor to do this either, just had to purchase three 5mm hex head screws from Ace Hardware.


Look at this link, Post #44 to see my descriptions of what I did to fix this, with pictures. http://www.infamousnissan.com/forum/...t=39952&page=5
__________________
2004 Frontier King Cab (2WD, 5-speed, 4-cylinder, 98.5K), 1998 Frontier regular cab (2WD, 5-speed, 4-cylinder 225K), 1988 Mazda B2200 (2WD, 5-speed, 4-cylinder, 214K), 1971 VW Convertible (140K), 2005 Yukon (180K), 1970 VW (260+K)
Cusser is offline   Reply With Quote
Old 08-11-2020, 04:55 PM   #7
david29
Administrator
 
Join Date: Sep 2008
Location: Spring(Houston), Texas
Age: 50
Posts: 6,121
Vehicle: 1987 Nissan King Cab
Thanks: 28
Thanked 539 Times in 482 Posts
Default

Just so you know, the AC compressor cycles on and off when the Thermo sensor detects its at optimal temperature. When it cools down to the temp it likes, it turns back on until it reaches the optimal level once again. Now the low pressure switch thats mounted on the dryer, will turn the compressor off when the freon gets too low. But I have seen these pressure switches fail by giving a false reading. But since you said yours was icing up because of constant running, the thermo switch is the culprit.
Now if your system just shuts down from time to time, as if you shut the system off, I would suspect the actual button switch on the HVAC controls might be going bad.
__________________
My stable of Nissan trucks includes:
1987 Nissan King Cab(full frame off Restoration).
david29 is offline   Reply With Quote
Old 08-11-2020, 10:19 PM   #8
joboy77
 
joboy77's Avatar
 
Join Date: Nov 2017
Location: Surprise, AZ
Posts: 51
Vehicle: 1997 Hardbody
Thanks: 16
Thanked 11 Times in 9 Posts
Default

Thanks for the help guys. So, my issue is that the compressor works great when it works, but will randomly not come on when I turn on the a/c or will randomly turn off and stay off after running for a while. The amount of time it will run is also random. The a/c button was the first thing I replaced with a brand new one. Did not fix the issue. I have tapped the compressor clutch to see if that would get it going and no go. The reason I suspect the thermo switch on the evap core is when I replaced the evap core and charged everything back up it was still doing the same thing. I took the plate off from behind the glove box to look and see if maybe I forgot to plug something back in and when I hit the wire the compressor kicked on and off. So I'm thinking broken wire or solder joint in the little circuit board. Next time it doesn't work I'll check for 12v at the compressor to see if the signal is getting stopped somewhere.
joboy77 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 06:04 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.