efan wiring help

Ok what am I doing wrong?? Efan going in 1993 240

Efan out of a 940T I believe. Bench tested and both high and low speed work

Volvo switch out of a 850 I believe

New temperature switch from NAPA(Fs150) threaded into the radiator.

High and low speed from volvo switch to temperature switch is there a high and low prong on the switch or are they interchangeable?)

Power from volvo switch to relay pin 87.

Relay pin 30 to inline 30a fuse, to positive battery terminal

Pin 85 to ground (efan also grounded)

Pin 86 to a switch

other terminal of switch to 12v power in car.

When I turn the car to power on (not running) and flip the switch, I can hear the relay click, but no fan.

I followed the diagram on The Ranger Station website: https://www.therangerstation.com/tech_library/volvo_electric_fan.shtml

am I supposed to ground the temperature switch somehow? If so how?

or bad volvo switch, idiot installer, a little of both?

orrob said:

Ok what am I doing wrong?? Efan going in 1993 240

Efan out of a 940T I believe. Bench tested and both high and low speed work

Volvo switch out of a 850 I believe

New temperature switch from NAPA(Fs150) threaded into the radiator.

High and low speed from volvo switch to temperature switch is there a high and low prong on the switch or are they interchangeable?)

Power from volvo switch to relay pin 87.

Relay pin 30 to inline 30a fuse, to positive battery terminal

Pin 85 to ground (efan also grounded)

Pin 86 to a switch

other terminal of switch to 12v power in car.

When I turn the car to power on (not running) and flip the switch, I can hear the relay click, but no fan.

I followed the diagram on The Ranger Station website: https://www.therangerstation.com/tech_library/volvo_electric_fan.shtml

am I supposed to ground the temperature switch somehow? If so how?

or bad volvo switch, idiot installer, a little of both?

Click to expand...

we are all partial idiots.
The Volvo relay is The relay, you don't need to use a second.
fused, big wires to allways ON power from bat and ground to relay

ground wire to sensor, then wire to one of the little terminals, low and high.

the other speed term can be switched to a ground source for manual activation. beware, you can leave fan on this way when you exit car, and therefore, you will do this at least once.

I wouldn't use the radiator sensor, use a SAAB tee and SAAB rad sensor in that tee, search noob.

search google, add "turbobricks" to efan, and whatever else you search, tis been answered too many times already. 99%Q's are well answerd already.
240turbo.com has some good info, you should read all the stuff there, wealth of info about all kinds of 240 stuff.

Yeah - run a wire from the Volvo relay to the temp switch, and from the other side of the temp switch to a ground. When the temp switch gets hot enough - it closes the circuit, grounding the terminal on the Volvo relay, and turning that speed (hi or lo) on.

FWIW the OEM temp switch on my radiator turned on at a pretty high temp. IIRC about 230 degrees. Not useful to lo (normal situations) speed fan switching. Instead, I used that as the dumb 'oh crikey' HI speed fan switch. And controlled LO speed via Megasquirt (turning on about 5 degrees higher than the thermostat temp - so if the car was getting plenty of airflow by driving fast - the fan would stay off). And if things got really hot, that 'failsafe' dumb switch would swoop in for the rescue with HI speed. I almost never heard HI speed kick in.

orrob said:

New temperature switch from NAPA(Fs150) threaded into the radiator.

High and low speed from volvo switch to temperature switch is there a high and low prong on the switch or are they interchangeable?)

Click to expand...

You need a dual temperature sensor, which should have 3 prongs - one high, one low, and one to ground. Sounds like you have a simple single temperature sensor, which will only work for 1 fan (pick the high or low fan, and ground the other side of the sensor).

As noted above, you don't need a second relay. The Volvo "switch" already includes dual relays to switch high/low fan power.

bobxyz said:

You need a dual temperature sensor, which should have 3 prongs - one high, one low, and one to ground. Sounds like you have a simple single temperature sensor, which will only work for 1 fan (pick the high or low fan, and ground the other side of the sensor).

As noted above, you don't need a second relay. The Volvo "switch" already includes dual relays to switch high/low fan power.

Click to expand...

yup, I run a inline fuse holder from the junction block near battery to the fat positive of the relay.

You've got a single speed switch, although not from a 850, they where switched by the ECU

According to napa:"On At 191-198 Deg. F., Off At 182-189 Deg. F. Descending Temperature."

To run the high and low speed you need either the saab switch mentioned above or a BMW 2 speed switch, that being said I only run the low speed and have yet to overheat so unless you are towing at above 100 I don't think you'll have issues

thanks guys. I got it sorted. I had seen the saab t but wanted to get it up and running quickly. I will probably swap it out or switch to the bmw one at some point.

orrob said:

thanks guys. I got it sorted. I had seen the saab t but wanted to get it up and running quickly. I will probably swap it out or switch to the bmw one at some point.

Click to expand...

Just make sure your power to that late 7/9 series relay is fused, or "fusible link" as the factory did. All of these radiator return hose / radiator switch solutions simply provide a ground path to actuate the Volvo relay. I'm running the SAAB 900 T in the return line as an additional ground path (OE supplied the ECU control as one, the A/C pressure switches as another). You may find the inrush when the brush DC motor engages, is borderline for your 30A fuse. I'm now running an 88*C switch for that ground in the TEE, but plan to raise it to the more common 92*C switch next time the coolant comes out.

When in doubt, check the OE design on the UK Volvo club 700/900 Maint. pages. All the wiring details can be found there.

In my 240, I used a Saab T with this dual temp switch placed in the upper radiator hose, it has a low of 85 and High of 92 or 93, can't remember, but it keeps me under the middle line on the temp gauge even on the hotter days of Cali. I know that's the true temperature because I removed the temp faker board inside the guage. We didn't use a secondary relay as the Volvo unit already is one, but for the power, we used an inline 30 amp fuse to the battery and also wired it to the inside fuse box with a 30 amp bullet fuse in there too. So now the fan is only on when my car is on. Without it set like that, the fan would stay on until it kills the battery.

I originally wanted to have a switch so I can turn on the fans when I want, but I figured I'd let the dual temp switch do its job and have the fans turn on automatically, been working perfect so far and the throttle response feels great now that there's nothing hanging off the front of the engine sucking power as it sucks in more air.