Electric fan install control by motor temp and AC compressor with one or two relays.

[Setzer]

Hello All I'm new to these forums. Recently my harmonic balancer went out. As I was staring to uninstall my fan and rad. to start the replacement I noticed my fan hub (the plastic part) was starting to crack very badly. So I decided to replace the fan with and electric one as it was much cheaper then a OEM style fan plus the HP and fuel milage gains I may get. Any way to point of my question. The fan is now install as per instruction to kick on/off using a temp sensor. I want to also have the fan come on when I turn my AC as I live in south Texas and the summers are very hot. I know there is something called a trinary switch that I can install to to accomplish this. The problem is I just reinstalled all new AC part and the AC is working perfect and I don't want to go messing around with it if I can avoid it. I want to know is there a way to use the one rely setup to have the fan come on when I turn the AC on? if not can I install another rely and instead of running to the ignition on power source could I just use the 12v on/off on the AC compressor or wire it into the controls in the dash? Here is a link of how it is installed now just mine had different color wires. https://www.griffinrad.com/PDFs/Wiring Diagram Single Fan.pdf . To those that do not understand what I am asking about I want to know is it safe to set a sconed rely installed they I'm ask? Because I am unsure of what will happen when the temp. senor gets hot enough to turn the fan on? will it back feed the AC comp, blow fuses and or relays? The only WEB search I found vaguely mentioned some thing about having to install diode, but did not say where.

 

[dvdswan]

Welcome to the site.

single electric fan with temp sensor and ac compressor install - Google Search

 

[Setzer]

I really hope that's not your advice? Because OMG why did I not think to search the %%^# web before I try and actually ask for real help!! Also the search results ether tell you to install using the trinary switch, nothing at all or just run a wire from then AC compressor to the power wire of the fan. That will not work as the AC comp and the fan will have to share the same power and one will be staving for power and this could damage ether part or just blow fuses all the time. But thanks for reading and understanding my post and the amazing advice!

 

[Rick]

I want to know is there a way to use the one rely setup to have the fan come on when I turn the AC on? if not can I install another rely and instead of running to the ignition on power source could I just use the 12v on/off on the AC compressor or wire it into the controls in the dash? Here is a link of how it is installed now just mine had different color wires. https://www.griffinrad.com/PDFs/Wiring Diagram Single Fan.pdf . To those that do not understand what I am asking about I want to know is it safe to set a sconed rely installed they I'm ask? Because I am unsure of what will happen when the temp. senor gets hot enough to turn the fan on? will it back feed the AC comp, blow fuses and or relays? The only WEB search I found vaguely mentioned some thing about having to install diode, but did not say where.

The way you described will indeed try to turn on the compressor when the temp sender triggers the fan.

The trinary switch is definitely the right way to go even though you will have to spend extra money for a recharge.

 

[Setzer]

The way you described will indeed try to turn on the compressor when the temp sender triggers the fan.

The trinary switch is definitely the right way to go even though you will have to spend extra money for a recharge.

Thank you I forgot to mention that too. That vague mention of using a diode was to stop this from happing but they did not go into details of where and how to install the diode/diodes. I can do a recharge myself but yes that's a lot of extra money along with trinary switch I do know want to have to spend over a $10.00 relay and few cents on a diode or two.

 

[donalds]

I'd buy a better fan controller. You will have problems
Buy one that has AC control

 

[Setzer]

I'd buy a better fan controller. You will have problems
Buy one that has AC control

I can not find any fan controller that will do what I'm asking and if they do they coast more then electric fan kit I bought and at that point I could have just gotten an OEM fan. I did find this Air Conditioning Relay Kit. But I'm not sure to install this if anyone could draw me a diagram using this I would be tremendously thankful and helpful! Are there no electrical engineers here?

 

[donalds]

.

 

[Setzer]

.

thank you! This will stop the back feeding of power to the AC comp.?

 

[donalds]

I imagine it would or it wouldn't sell very well

 

[Setzer]

I imagine it would or it wouldn't sell very

 

[Setzer]

.

Well it's just a simple 4 pole relay and I have coming tomorrow so I guess I can make one myself and hook it up and see what happens. If it dose not work. I did find more info. on using a diode. If I install the two of the proper size and amount of diodes on the power wire for the fan using the temp senor and another one on the power wire to the fan using the AC control it will stop them from back feeding to each other.

 

[dvdswan]

I really hope that's not your advice? Because OMG why did I not think to search the %%^# web before I try and actually ask for real help!! Also the search results ether tell you to install using the trinary switch, nothing at all or just run a wire from then AC compressor to the power wire of the fan. That will not work as the AC comp and the fan will have to share the same power and one will be staving for power and this could damage ether part or just blow fuses all the time. But thanks for reading and understanding my post and the amazing advice!

If you did a proper search you would have found this... It's generic but you might get the point. Next time just be thankful someone offered you something for free

 

[lincolnlocker]

Hello All I'm new to these forums. Recently my harmonic balancer went out. As I was staring to uninstall my fan and rad. to start the replacement I noticed my fan hub (the plastic part) was starting to crack very badly. So I decided to replace the fan with and electric one as it was much cheaper then a OEM style fan plus the HP and fuel milage gains I may get. Any way to point of my question. The fan is now install as per instruction to kick on/off using a temp sensor. I want to also have the fan come on when I turn my AC as I live in south Texas and the summers are very hot. I know there is something called a trinary switch that I can install to to accomplish this. The problem is I just reinstalled all new AC part and the AC is working perfect and I don't want to go messing around with it if I can avoid it. I want to know is there a way to use the one rely setup to have the fan come on when I turn the AC on? if not can I install another rely and instead of running to the ignition on power source could I just use the 12v on/off on the AC compressor or wire it into the controls in the dash? Here is a link of how it is installed now just mine had different color wires. . To those that do not understand what I am asking about I want to know is it safe to set a sconed rely installed they I'm ask? Because I am unsure of what will happen when the temp. senor gets hot enough to turn the fan on? will it back feed the AC comp, blow fuses and or relays? The only WEB search I found vaguely mentioned some thing about having to install diode, but did not say where.

I'm trying to understand how to activate dual fans with AC. I have an E38 PCM and a SPEARTECH harness, Vintage air and dual fans. Speartech calls for fan One and fan Two. the harness has dedicated 12v + (keyed) and ground (switched) signal for each fans. So when I add AC now I need to activate both fans at AC on through trinary switch. When I contacted speartech they said to split the AC on signal to each relay. My concern is that when I combine both relays to the one AC on signal that I am essentially tying the fan one and fan two signal from the pcm together and both fans will come on when just fan one is activated by pcm. My thinking is that I will need two additional relays to keep the signals separated, correct?