Dash Air Not Working
I have a 2006 Tiffin Allegro Bay on a Workhorse W24 chassis. The dash air will not come on. Local shop determined that the relay under the hood that pulls in the compressor clutch was not working. T...
Forum Discussion
Yes the system has the proper amount of R134A - low pressure switch is ok (closed). Have yet to test the high pressure switch.
Going back to the schematic - this is a Denso wiring diagram I got by getting the part number off the dash control and searching the web. The schematic is for the interior heat/cooling unit inside the cockpit. According to Tiffin AC service tech the Denso unit sends a 12V signal (the output of the "Magnetic Clutch Relay" pin 3 at top of page) to the Workhorse chassis. I believe the part shown to the right of the label "Light Switch" is a generic destination since Denso doesn't know what vehicle their unit is installed in.
Under the hood the diagram in the cover of the fuse center shows a 10A fuse labeled "Comp" and a relay labeled "Comp". This fuse and relay feed the compressor clutch.
When I depress the AC ON button on the control panel it applies 12V to one side of the coil and to the contacts. All I need is a ground to the other side of the coil - this must come from Workhorse installed sensors like the Hi and Low pressures switch's.
As a retired EE I have 48 years electrical experience and I am EPA certified in HVAC including mobile - but without a schematic for the Workhorse side I am flying blind.
Since there is protection for pressure and temperature in the Denso unit I think I can safely permanently ground the relay coil under the hood and forget figuring out what it should be..............
Going back to the schematic - this is a Denso wiring diagram I got by getting the part number off the dash control and searching the web. The schematic is for the interior heat/cooling unit inside the cockpit. According to Tiffin AC service tech the Denso unit sends a 12V signal (the output of the "Magnetic Clutch Relay" pin 3 at top of page) to the Workhorse chassis. I believe the part shown to the right of the label "Light Switch" is a generic destination since Denso doesn't know what vehicle their unit is installed in.
Under the hood the diagram in the cover of the fuse center shows a 10A fuse labeled "Comp" and a relay labeled "Comp". This fuse and relay feed the compressor clutch.
When I depress the AC ON button on the control panel it applies 12V to one side of the coil and to the contacts. All I need is a ground to the other side of the coil - this must come from Workhorse installed sensors like the Hi and Low pressures switch's.
As a retired EE I have 48 years electrical experience and I am EPA certified in HVAC including mobile - but without a schematic for the Workhorse side I am flying blind.
Since there is protection for pressure and temperature in the Denso unit I think I can safely permanently ground the relay coil under the hood and forget figuring out what it should be..............
