Electric fan wiring

[Distro]

Wired up electric fan and it works fine. Problem is my temperature gauge is not working. I have an idea why. I spliced the wire from the fan that goes to the temperature sender in with the wire that goes to my temperature gauge. Is there a way to get my gauge working?

[RustyPile]

Originally Posted by Distro

Wired up electric fan and it works fine. Problem is my temperature gauge is not working. I have an idea why. I spliced the wire from the fan that goes to the temperature sender in with the wire that goes to my temperature gauge. Is there a way to get my gauge working?

You have to add an additional sensor/temperature switch to the fan wiring.. The gauge sensor isn't capable of accurately operating both the fan and gauge.. This is the system I installed on my truck to control the radiator fans..

https://www.summitracing.com/parts/der-16759

[Sheepdip]

Have no idea about your gauge as far as if it's still going to work. I'd try a new temp sender first. You need a different type of sender for the fan trigger and it should trigger a relay other wise you'll burn it up using it as a fan motor ground, too many amps required.

Also don't know how you wired your fan either but here is the proper way. I use a 40 amp auto reset fuse and one for each fan if multiples

[Andy4639]

I assume you used the sender for a ground wire to the fan. If so it want work for the gauge to.

I would go to the parts store and buy one of the adjustable termostatic controllers and run it off that. That is the simplest way. This is a standard kit. You can buy them with relays also. They have some as much $200.00 if you want them.
I just buy this kit and a relay to hook up in mine.
I add a speed switch also to mine to cut the fans off when I'm at road speed. No need to run the fans when you don't need them.

[Rickysnickers]

I have one of these on my truck. The only thing I do not like about it, it that it runs after the truck has been turned off. Is there a way to stop that from occurring?

Originally Posted by Andy4639

I assume you used the sender for a ground wire to the fan. If so it want work for the gauge to.

I would go to the parts store and buy one of the adjustable termostatic controllers and run it off that. That is the simplest way. This is a standard kit. You can buy them with relays also. They have some as much $200.00 if you want them.
I just buy this kit and a relay to hook up in mine.
I add a speed switch also to mine to cut the fans off when I'm at road speed. No need to run the fans when you don't need them.

[Andy4639]

Originally Posted by Rickysnickers

I have one of these on my truck. The only thing I do not like about it, it that it runs after the truck has been turned off. Is there a way to stop that from occurring?

Yes, depending on how you have it wired. If it keeps running after the truck is turned off you have it straight wired to 12 volts.
If it runs 12 volts straight off the battery you will need to put either a on/off switch in line at the dash area so you can shut it off but that sometimes isn't good enough because you forget to shut it off.
With a relay that shuts power off with the key switch is the best. Just cut the truck off and it will cut off. When you crank it up it want come on until the temperature is reached by the adjustable thermastat.

[Distro]

I plan on calling champion radiator tommorow and see what they recommend. I've called them once already and the costumer service was great. I'll update after I speak to them.

[HO455]

Originally Posted by Distro

Wired up electric fan and it works fine. Problem is my temperature gauge is not working. I have an idea why. I spliced the wire from the fan that goes to the temperature sender in with the wire that goes to my temperature gauge. Is there a way to get my gauge working?

The sender for the guage is a resistor calibrated with the guage to make the needle approximate the engine temperature. Hooking the fan to the sender changes the resistance seen by the guage preventing it from working correctly.
The fan needs to have a temperature switch to operate correctly. Ie a switch that operates at a certain temperature. Hooking the fan directly to the sender just makes the fan run slower. It won't turn the fan on and off based on engine temperature.
There isn't any reasonable method of using the temperature sender to turn the fan on and off.
The temperature switch that was used on the idiot lights is the right kind of switch but the temperature switch set point is too high to operate cooling fans.

[MARKDTN]

For a single speed fan I would just put a 180 or so sensor (like Cole-Hersey 84251) in the intake if you have aftermarket intake or RH head if you have stock intake (that plug can be a pain to remove) or water neck. Use that signal to ground a relay. So on a 70A Bosch type relay (Cole-Hersey RA700112DN-BX), battery hot to 30 , fan hot to 87, ground from the sensor to 85, and ignition switched to 86. So if the coolant is hotter than the switch and ignition is on then the fan runs.

For a 2-speed fan I use a BMW switch in intake, water neck, or head as above. BMW p/n 61318361787 is 180 low and 195 degrees for high speed. Use a Volvo relay (1398845) to control high and low speeds. Both of these have unique plugs so you are better to buy used and get plug and relay or sensor. I add a main relay so it does not run with ignition off. On a 70A Bosch type relay (Cole-Hersey RA700112DN-BX), battery hot to 30 , Volvo relay hot to 87, ground to 85, and ignition switched to 86. Then Volvo relay LH 1 to fan low speed and LH 2 to high speed. Then Volvo relay Center 1 to the low side of the BMW switch and Center 2 to the high speed side. BMW switch if you are looking at the pins with the flat side down, then ground goes to 12, low at 9 and high at 3 o'clock. So if the coolant is hotter than 180 and ignition is on then the fan runs on low. If the coolant is hotter than 195 and ignition is on then the fan runs on high.

Note that the BMW switch is M14x1.5 thread. I bought a 3/8 to ¼ bushing and drilled and tapped it M14. Also note that you should use a fuse or circuit breaker on the power supply to the relay for protection.

[fdbdw]

Another option is to remove the radiator drain plug and install the sending unit in its place. That’s what I did , works great.

[Peanut74]

Thanks for the idea fdbdw. I am just about to the point where I will need to hook up my fan. I went with a electronic gauges and electric fan so I have the same dilemma two sensor fighting over the same hole. So this is a good second option to the radiator probe route.

[68 P.O.S.]

I'm using the dual fan relay kit from Champion. They have a single fan kit too. I didn't use their sending unit for the intake tho, I bought a different one that goes in the rad. Also have a zinc anode in the rad drain plug as well.

https://www.championradiators.com/dual-fan-relay-kit

[guyryan100]

In modern cars the fan will continue to run for a short period even after ignition is turned off, has anyone seen a relay kit that will do that without running the fan so long that the battery is drained? If so that would seem good for cooling. I notice that immediately after the engine is cut, temperatures in the radiator rise rapidly.

[Sheepdip]

Originally Posted by guyryan100

In modern cars the fan will continue to run for a short period even after ignition is turned off, has anyone seen a relay kit that will do that without running the fan so long that the battery is drained? If so that would seem good for cooling. I notice that immediately after the engine is cut, temperatures in the radiator rise rapidly.

That's called a delay relay, they make them to go both ways, delay on or delay off.

[MARKDTN]

Hella 996152131 - Hella Adjustable Time Delay Units appear to fit a regular Hella/Bosch style base. They are rated at 20A so not enough to run a big fan, they would have to be added and used to trigger the larger relay. So in my description above, the new relay would be battery (fused) hot to 30 terminal, ignition switched power to 86, ground to 85, and out to the ignition (86) on the big 70A relay from 87. That way the ignition supply would have a delay of whatever you programmed the relay for.