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Smed · 07-14-2010, 06:12 PM

Front control for levels, radio, gen. extender, driver fans all stop working. Disconected PDM once and sounded like it reset and worked for a while, but stoped working again. Checked all fuse, but can't find problem. Unknow how to check the PDM. all lights on PDM come on, but can't find proble.

EngineerMike · 07-14-2010, 07:53 PM

I don't have the coach here or I'd check which PDM lights should be on w/key off, key on, and key on engine running. I'm wondering if you have a PDM problem at all if the LEDs are on generally. Seems to me from recollection (be careful cuz this is after two Guinness Draught's & I'm thinking about popping open a 3rd) that one bank of LEDs lights regardless, and both light w/key on, but remember that's the besotted memory of a bumbling half wit.
On the VMM below the PDM there are two LEDs, one for power & one for network. The power LED should be steady on, and the net should be blinking showing traffic over the "network" which is the twisted pair between the front & back VMM; I believe the VMM twisted pair is tied into the J1939 chassis network but have never actually verified that. If the VMM is dead, it could be no power from the PDM. Here is a table, courtesy of Bigfish, for the 05 PDM. I don't think Inputs 13-17 exist but were just numbers in his table.
Hope this helps.

INPUTS.......................OUTPUTS
1 IGN/ACC IGNITION.....1A, 1B, 1C HVAC
2 IGN/ACC IGNITION.....2 MIRROR
3 IGN/ACC IGNITION.....3 RADIO
4 IGN/ACC IGNITION.....4 STEP COVER 5 IGN/ACC IGNITION.....5 HWH ACC
6 IGN/ACC IGNITION.....6 AUX-POWER-ACC
7 BATTERY ENABLE........7 SSR1/SSR2 BATTERY
8 BATTERY ENABLE........8 AUX POWER-BATTERY
9 BATTERY ENABLE........9 STEP MOTOR 1
10 BATTERY ENABLE......10 STEP MOTOR 2
11 BATTERY ENABLE......11 PEDAL ADJ/ELEC BATTERY
12 BATTERY ENABLE...... 12A WIPERS
.................................12B WIPERS
.................................12C WIPERS
.................................13 IGN/ACC POWER 1 .................................14 IGN/ACC POWER 2

Smed · 07-14-2010, 09:25 PM

Thanks Mike. First it is now working. But when it wasn't and the key on all the lights on the PDM were on, but the power light on the MM was blinking and only a couple of lights were coming on. When i fliped the drivers fan switch on one of the lights would come on, but no fan. The net light has not come on.
I decied to completly disconnect the neg. side of the eng. batt. then re-attach it. Still nothing. I then disconnected all the power and plugs going into the PDM...wait a few seconds then reconnect all the plugs. It started working. Now i'm afraid if I turn the shut-off batt. switch off while parked because I might again have the same problem.

Smed · 07-15-2010, 05:54 PM

Mike thanks again. The problem is back. I turned off my main batt. connector for about a hour. When i turned it back on it didn't work again. With the key both on and off, The VMM power light was blinking and the net work light was off. I unpluged the PDM re-pluged, but still nothing. I then unplug the PDM again and before re-attaching the plugs I turned the key to acc. with the key on I re-pluged in the PDM and this time it worked, lighting up 7-15-16-17 & 19 in the VMM. Somewhere there's a problem, but ?

EngineerMike · 07-16-2010, 05:37 PM

From the Vansco VMM manual:
The power LED has three states, ON, OFF, and FLASHING.
• If the LED is ON, the module is powered up and is operating normally.
• If the power LED is OFF, the module is either in Power Save Mode or the
vehicle power has been completely disconnected.
• If the LED is FLASHING, the module is powered up but currently has no
vehicle configuration loaded into it or there is an internal VMM fault.
The diagnostic LEDs are designed to simplify vehicle debugging. Each LED
represents an input or output and as such, each LED is essentially a circuit
continuity tester. An indication of an electrical fault condition on a diagnostic
LED should be investigated and corrected immediately to prevent system
damage.

I'll see if I can get the manual posted on the ACA Tech Library.

dgerstel · 07-17-2010, 06:38 PM

I haven't had a problem with the PDM, but have with both VMM modules. When the modules are working correctly, any single short would only affect one circuit. When my modules failed, they were acting more like yours is. They failed one at a time, front first (no lights) and later the rear. (no starter)

You didn't state what year coach you have. I was told by Vansco that there was a bad batch of units at the time mine were produced.