I can't remember at what temp the Haldex heater comes on.
Anyone?
Can't tell you the exact temperature, but all air dryers I have worked on have them. The dryer would cease to function in below freezing temperatures (can't purge ICE) were it not for the heater.
I guess I can wait until the temp gets down around 32F and feel if it's warm with the ignition on.
yes they are designed to come on once it senses freezing temps. There is a little button temp sensor on the underside of the plastic part that sits in a recess in the bottom outside housing and "feels" the casting temperature. This is the "switch" for closing the circuit and applying the 12volts to heat.
One item I think that gets overlooked on the Pure Air model is the Turbo Valve. This should be changed as well and is part of one of the kits for major lower service DQ6026.
JohnH
So is the heater on
anytime the dryer casting temp is below freezing, or does heater only function with ignition switch "ON"?
If it is on anytime it freezes, this could be another "phantom" drain on the (start?) batteries.
But if it only works with ignition switch on, then the purge valve could potentially be frozen every time you start engine in below freezing temps.
Chuck,
Should be powered by an "ignition hot" source. But, easy to confirm-- just unplug the pigtail from the dryer and check for voltage with ignition OFF and then ON.
Do as I say, not as I have done.
When receiving a new (rebuilt) unit check that it has a heater installed !
If not, use the old heater, after checking with a 12 volt supply
CHECK AND INSTALL BEFORE MOUNTING THE UNIT !!!!!!!
very difficult to install after unit is in place.
Chuck,
On the Unicoach (like up till at least '03) the heater is fed off a breaker that is hid in the breaker panel behind the kick panel just in front of the passengers seat. It only has power when the key is on. I don't recall the exact breaker # but it is shown on the B-2179 print.
I don't remember where the breaker is located in the Grand Villa's.
Pamela & Mike
#16 on a 2003 U320. Has white wire L3 running from it to the air dryer. Not sure if it would be the same for a U295.