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Topic: Help!---Dash Blower just quit in Aquahot mode (Read 618 times) previous topic - next topic

Help!---Dash Blower just quit in Aquahot mode

I have a few questions relating to the dash blower on my 2001 U320 that I haven't found covered in the forums.

1.  This week dash blower quit working (of course it happened right when the temps are crashing to near zero here).  Checked to make sure that all the wires were secure to the dash relay, so without doing any more trouble shooting, guessing that relay may have failed...new relays on order.  Works fine with ign on.  Anything else I could check?

2.  The other thing I noticed prior to this episode, is that when the dash blower was on in AH mode, ign off, I could change the dash fan speed with the passenger 3 position fan switch...i.e. loud and not so loud.  Anyone else noticed this?  Could you please let me know one way or the other.  I may have a bigger wiring issue than just the relay.

Thanks in advance...Woody.

Re: Help!---Dash Blower just quit in Aquahot mode

Reply #1 –
Woody,  See
Aqua Hot Dash Blower Fan Override

There is an ignition controlled relay that enables the fan use with the AH with ignition off or disables it with the ignition on.

I have not noticed that the dash fan speed control would have any effect.  It is usually off when we are using the AH for heat.

Re: Help!---Dash Blower just quit in Aquahot mode

Reply #2 –
Roger, assuming that's the relay you show in the override link, right?  When I was checking security of the wires in that relay vicinity yesterday, I must've found a momentary short somewhere deeper, as later that afternoon, discovered I'd lost all heat register blowers.  Dug out the Aquahot manual and went belly cave diving into the bowels of the AH during a 25F snow storm to find 10A fuse D (blower fans) blown and replaced it...got back the register fans but dash fan still not.  Went down to 10F last night, so glad I got that back up and running.  BTW, AH, what a dumb place to put fuses...inside the sealed heat chamber, couldn't put a fuse block on the outside of the case?  So I now don't think the relay is the issue, rather a wire has pulled loose from a connector, and of course buried in the dash.  I ordered a 4 pack of relays and will resume dash digging and trouble shooting when they arrive and after it warms up a bit...will also add the switch you conjured up.

For the other question, the dash fan speed control had no effect...it was the 3 position fan speed control to the right of the passenger seat that changed the dash fan speed (hi/lo) when in ign off AH mode.

Woody.

Re: Help!---Dash Blower just quit in Aquahot mode

Reply #3 –
Today I tore into the dash, replaced the relay and checked all the wire connections to the relay.  No dice.  Dash fan still didn't come on with AH living room heat.  I could hear relay's clicking but fan wasn't coming on.  I know both fans and their relays are all good as I replaced them last year and they both work on all speeds with the IGN on.  The power feed to the relay comes out of a A/C Logic Controller box right next to the relay.  It's made by Javelina, and therefore guessed it's unobtaneum and not repairable.  So I gave it a whack with my fist and went to the PC to see if I could find a schematic for the damn thing.  The LR heat came on and about 20 seconds afterward, all by itself, the dash fan kicked on.  What the hell?  It's been working fine all afternoon/evening since.  I put in Roger's switch and buttoned up the dash.  Still working fine.  I don't like it when things don't have a definitive fix but I'll take it.

However, I'd still like to know if anyone else can control the intensity of the dash fan in AH mode by changing the fan speed on the passenger side wall fan switch.  If I have a faulty ground path, I'd sure like to know.  If no one answers I'll post a poll.  Thanks,  Woody.
 

Re: Help!---Dash Blower just quit in Aquahot mode

Reply #4 –
In my coach I can't control the dash fan speed in Aqua Hot mode from the dash or the the passenger side.  My dash blower is just one speed like the rest of the blowers.  Will be installing the switch as Roger suggested.
John M.