Thread: Blower fan power draw

depends on which one you have, I've seen 7 amps but they average about 5

High draw can result in blown relays. Check your pollen filters!

Originally Posted by Craig_Keira

High draw can result in blown relays. Check your pollen filters!

Thanks for the input. I think the theory of blocked pollen filters has been dismissed by those far brighter than I am. Do a search on RangeRover.net for additional info
In my first post about Hevac fans I put Relays and fuses ok. I looked there 1st. Not only my pollen filters but also my plenum filter is in top shape unlike 99% of cars I have seen

The reason I asked about power draw was if all else failed I would get the blowers running direct from the battery through a DC PWM speed controller as a temporary fix. I have taken the fans out and they are fine and its easy to run them directly, disconnected from the hevac control. I needed to know what size Amperage speed controller I would need. I am off on a long trip in two weeks so by then the fans will be running even if I have to buy two Hamsters to power them.

http://www.ebay.com/itm/PWM-Converte...item27cc2c0a74

I can't remember what your problem is.

The fans don't normally come on at all, they are controlled by the pressure switches on the receiver dryer and only operate when these switches decide that the pressures in the air con system are too high or too low or some such.

They don't respond to temperature, just pressures.

The easiest way to test them is to short circuit the single pressure switch and turn on the air con system.

From under the front of the car, look up and you will see the receiver dryer. There are two pressure switches on the air con gas lines from the dryer. One will have two wires, and the other will have three.

Pull the plug from the one with 2 wires and put a bridging wire between the 2 points, start the car and turn on the air con.

The fans should now work as the system sees that the 'pressure' switch has closed.

As a safety measure I have wired this switch to the new temperature monitor I have installed. When the temp gets to 98c the air con fans come on to help drop the temp, then go off when its back to 89c.

Regards
Trevor

I don't know if wires got crossed here, but I'm pretty sure old mate is asking how much power/current the blowers (the ones that blow cold air into the cab) draw! He wants to get a speed controller to run the blowers as an interim measure for his trip!

Thats what I thought Keith, but as an interim measure he could try just shorting the pressure switch.
Apparently he know the fans work, so the problem is probably somewhere in the air con system.
Worth a try and quite easy to do.

Regards
Trev

ummm pressure switches control the condenser fans behind the grill, blower motors have permanent 12V controlled by feedback from HEVAC ... think Wayneg is referring to the in-cabin blower motors... I haven't worked out whether part of the feedback mechanism from the HEVAC module to the blower motors is dependent also on the requirements of the condenser fans controlled by the dryer pressure switches

I am discussing the in car blowers, they should work regardless of aircon. Rave says there is a permanent poss+ feed to the motors. The speed is controlled through the earth by the Hevac control panel.
I have no Poss+ getting to my fans from the fuse box. As stated if all else fails I will just run a direct cable from the battery.