Fan control with AC and 05 fans on DBC truck
04-06-2016, 11:51 AM
#41
Teching In
Join Date: Jul 2013
Posts: 35
Likes: 0
Received 0 Likes
on
0 Posts
did you get this figured out and working?
im 99% sure you can add the 3 wire AC pressure sensor like the 4thgen f-body uses and set the PCM for analog AC type. that would allow the fans to cycle on and off with AC pressure instead of just anytime the compressor clutch is engaged.
im 99% sure you can add the 3 wire AC pressure sensor like the 4thgen f-body uses and set the PCM for analog AC type. that would allow the fans to cycle on and off with AC pressure instead of just anytime the compressor clutch is engaged.
04-06-2016, 12:36 PM
#42
Yea, my method works just fine. The only difference being the fans are always on high with the AC, as opposed to possibly being on low or high depending on pressure. Honestly im sure they would at least be on low any time the AC is on.
I certainly could add the AC pressure sensor, but thats $50 worth of sensor and pigtail and running some wires, so I just used a relay I have on hand (free) to do the same thing with a smidge less level of control.
I certainly could add the AC pressure sensor, but thats $50 worth of sensor and pigtail and running some wires, so I just used a relay I have on hand (free) to do the same thing with a smidge less level of control.
04-06-2016, 03:19 PM
#43
The reason I would want the PCM to fully control the fans based on AC as well is so that the fans don't come on while I am on the highway when they are not needed. I have even considered adding a relay that is disconnected at a certain speed much like the reverse lockout feature...
Now that I typed that out. The PCM should already have this feature. Just might have to change the OS to one that had a t56 for the lockout to work which I can then use to disable the fans at speed. I would assume that speed can be changed. I guess we'll see.
Now that I typed that out. The PCM should already have this feature. Just might have to change the OS to one that had a t56 for the lockout to work which I can then use to disable the fans at speed. I would assume that speed can be changed. I guess we'll see.
04-06-2016, 03:36 PM
#44
Ya know, I heard that rumor that above 40-50mph the fans dont really do anything. I tested it. Cruising at 70-75 if I turn the fans on high I can drop ECT down to the thermostat setting, otherwise it sits at +10 or so. Not a huge difference, but the fans absolutely help move more air across the radiator and condenser even when you are moving at speed.
04-06-2016, 03:51 PM
#46
Ya know, I heard that rumor that above 40-50mph the fans dont really do anything. I tested it. Cruising at 70-75 if I turn the fans on high I can drop ECT down to the thermostat setting, otherwise it sits at +10 or so. Not a huge difference, but the fans absolutely help move more air across the radiator and condenser even when you are moving at speed.
When I'm on the highway my ects drop to low 160s. In town my fans keep temps where i set them usually 178-188. I haven't tried fans on the highon the highway as i haven't seen the need, my pcm automatically turns them off above 50 mph.
I do have an aftermarket all alum rad.
06-21-2019, 05:16 PM
#48
Registered User
Join Date: Jun 2019
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Yea, my method works just fine. The only difference being the fans are always on high with the AC, as opposed to possibly being on low or high depending on pressure. Honestly im sure they would at least be on low any time the AC is on.
I certainly could add the AC pressure sensor, but thats $50 worth of sensor and pigtail and running some wires, so I just used a relay I have on hand (free) to do the same thing with a smidge less level of control.
I certainly could add the AC pressure sensor, but thats $50 worth of sensor and pigtail and running some wires, so I just used a relay I have on hand (free) to do the same thing with a smidge less level of control.
any suggestions?????
06-21-2019, 06:59 PM
#49
It sounds like the relays aren't wired correctly. My fans both come on low at temperature, and both high with A/C. I am going to add a thermostat to turn both fans on high when the coolant gets hotter. It will energize the same wire that the A/C energizes, with a diode on the A/C side to keep from energizing the A/C clutch.