I am finally getting around to fixing something that has never worked on my bus. The warm air blower. The idea is to finally get the heater working. I took the snail fan out and put it on a battery - it's a runner! so that's a good start. Next I'll test the relay and check that is good. I have a couple of questions though. The Bentley manual suggests there is an inline fuse off of the actual heater control arm but my Haynes makes no reference to this. Any views. Bus is 1975. I know I'm going to have to get under the bus to check the cables, heater flaps etc. but for now I'm focussing on the fan. Anything else I should be mindful/aware of?
Yes there is an inline fuse 8amps I think, the fan only operates with the engine running when one of the red levers are in the full down position as there is a micro switch that completes the circuit. I repaired mine earlier this year , I will have a look tomorrow and post a pic of the wiring and a diagram.
As above the red leaver has a metal contact they tend to ark I retro fitted a micro switch and added a 30amp relay, the one on the back of the snail fan usually suffers from corrosion
I've had this discussion before but as I think 78 on they were wired to work ign on, not engine running only!
Checked the relay at the fan. Put current across it and got a click. Then did the same again but with the meter across the other pins checking resistance. Got 0 ohms so am happy the relay is good. Switch up front and inline fuses next...
There is a red wire with the fuse holder attached coming from the right hand side which ten connects to the relay. I have attached a wiring diagram and key from a 1976 Bus that helped me to understand the logic of it, hope it helps
theres also a write up on the samba, maybe worth a read https://www.thesamba.com/vw/forum/viewtopic.php?t=293787
We have progress. So having checked the fan on a spare battery as well as the relay I put everything back in. Checked the brown and white wire with ignition on and the lever at the dash up. I got 0V, I checked the green wire which is opposite on the relay and got 12v. Live wire to relay also showing 12v when engine on so I know that if that relay trips then I'm going to get juice to the fan. Depressed heater lever, no fan and no change of voltage at the wires either. Got under the dash and checked the contact at the lever - looked a bit manky so got some fine wet and dry on that (doing my best Ali Bongo impression to get to it - he was a contortionist you know...) - went for it again - nothing. Even though I'd replaced the fuse I checked it for resistance and it was duff. Replaced it, set the lever up, fired up the engine and dropped the lever - SUCCESS!!! Fan spinning like a spinny thing. Lever up, fan stops. Now here's the final hurdle. Lever down - fan stopped. Checked again and yep - it blew the fuse. I'm using a 10amp in-line mini blade type. My question - do I simply put a higher amp fuse in or is this symptomatic of some other problem. Clearly the fan was happy to spin when the lever dropped so not sure why the fuse would blow.
Just found in Bentley that it states the in-line fuse for warm air blower is 16amps. Will get one tomorrow and see what happens...
15amp fuse fitted (coud not find 16amp blade type) - job done. lever down - fan on, lever up fan off, repeat, repeat, repeat. Next up - flap inspection and checking for gaps in the heater tubes - and probably blanking off the junction to the rear of the bus...
