Wire Fan to A/C Switch
#1
09-09-2023
Wire Fan to A/C Switch
1993, MT, 2WD
Need some help from the guys that have added the dual speed electric Volvo fan to your Ranger. How do you wire the fan to turn on when the A/C is turned on?
Right now I have it set to turn on with a temp sensor in the upper radiator hose. When the A/C is on before the truck to warm enough, the condenser will get too hot and the high pressure A/C hose will push all the freon out.
My thought is that I wire one speed to the temp sensor in the upper radiator hose and then second speed fan to the A/C switch. You think this will work?
Need some help from the guys that have added the dual speed electric Volvo fan to your Ranger. How do you wire the fan to turn on when the A/C is turned on?
Right now I have it set to turn on with a temp sensor in the upper radiator hose. When the A/C is on before the truck to warm enough, the condenser will get too hot and the high pressure A/C hose will push all the freon out.
My thought is that I wire one speed to the temp sensor in the upper radiator hose and then second speed fan to the A/C switch. You think this will work?
Last edited by art1029; 09-09-2023 at 09:56 AM.
#2
09-09-2023
Temp switch on upper rad hose should be place so its on the side or lower part of the hose in case coolant gets low, these "sensors" can't read air temp just liquid temp
AC systems use 12volt activation, the Volvo system uses Ground activation,so no they can not be hooked directly together
You need a 12v relay to activate fan with AC on, because your temp switch is a Ground control switch, which Volvo Dual speed switch should be, like this diagram: https://www.jeepz.com/forum/attachme...lvo-wiring.jpg
The AC clutch will get 12v when activated, you will use that 12v to activate the added relay, relays are low amp draws so it won't cause AC Clutch fuse issues
The relay will be a Ground Relay, so when off no ground, when on grounded
This will be hooked to low speed ground wire on temp switch, or high, your choice
Standard automotive 12v mini relay looks like this: https://www.gtsparkplugs.com/images/...iring-840x.jpg
This is a 5 pin relay, but you don't need the 5th pin so can used a 4 pin relay, it doesn't have 87A
85 and 86 are used to active the relay, if one is grounded then 12v on the other activates the relay
When activated 30 and 87 are connected together
So you will run a ground wire to 85 and 30, so both share the same full time ground
Then 1 wire from AC Clutch 12v wire to 86, to activate relay, splice it to the 12v wire
And 1 wire from 87 to temp switch Low or high ground wire, splice it to the temp switch wire
When activated it will be the same as if the temp switch activated the fan, grounding the Volvo relay for that speed
And it won't effect temp switch operation when AC is off
12v 30/40a relay WITH wired base(plug in) are $20 at most auto parts stores, online 2 for $15
AC systems use 12volt activation, the Volvo system uses Ground activation,so no they can not be hooked directly together
You need a 12v relay to activate fan with AC on, because your temp switch is a Ground control switch, which Volvo Dual speed switch should be, like this diagram: https://www.jeepz.com/forum/attachme...lvo-wiring.jpg
The AC clutch will get 12v when activated, you will use that 12v to activate the added relay, relays are low amp draws so it won't cause AC Clutch fuse issues
The relay will be a Ground Relay, so when off no ground, when on grounded
This will be hooked to low speed ground wire on temp switch, or high, your choice
Standard automotive 12v mini relay looks like this: https://www.gtsparkplugs.com/images/...iring-840x.jpg
This is a 5 pin relay, but you don't need the 5th pin so can used a 4 pin relay, it doesn't have 87A
85 and 86 are used to active the relay, if one is grounded then 12v on the other activates the relay
When activated 30 and 87 are connected together
So you will run a ground wire to 85 and 30, so both share the same full time ground
Then 1 wire from AC Clutch 12v wire to 86, to activate relay, splice it to the 12v wire
And 1 wire from 87 to temp switch Low or high ground wire, splice it to the temp switch wire
When activated it will be the same as if the temp switch activated the fan, grounding the Volvo relay for that speed
And it won't effect temp switch operation when AC is off
12v 30/40a relay WITH wired base(plug in) are $20 at most auto parts stores, online 2 for $15
Last edited by RonD; 09-09-2023 at 12:27 PM.
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