mobilehomerepair.com

hello, i have a coleman model 3500 A816 and am now trying to get the heat working for winter i had some issues early in year with ac not cycling on /off properly and ordered the reversing relay installed it and it worked correctly all season.... now upon switching front of unit to heat /auto the element gets red hot however the blower wont kick in. the blower does come right on when switched back to ac mode also the continuous blower(on) function is not working on eitherheat nor ac mode .thanks for reading any hints would be greatly appreciated

Hi,

Could be a sequencer, fan relay or on/auto switch problem. Could also be a loose or disconnected wire.



Thanks,
Robert

Robert, thank you for your quick reply .the thing is the harness plugs had moisture from a dripping a coil and shorted last year so i bypassed plugs and wired direct had no issues until now with heat or ac . do you know if i can get just the 2 plugs with enough wire to hook into the existing wires?if so pherhaps you can give me part # i will order from your site as my last order arrived quickly and was priced perfectly.i have a very hard time finding the correct parts on the site as i dont know much about the correct names of components . just was curious IF when i changed the reversing relay the connections were a little different from the OE but it did work on ac i had not tryed heat until now .i do have a orange wire w/white stripe that goes nowhere it comes from the controls on front to the old plug .

Recheck your wiring one by one with the wiring diagram. If you do not have a wiring diagram, Mark sells them and sends them by email.


We sell the molex connector plugs, the pins inside them and the wire. Would be best to get enough wire for full connection on each without any splices.


First, though, ensure the wiring is correct.

The reversing relay is not in the heating circuit.



Thanks,
Robert

thanks again i have gotten a harness ,control box,and blower assy from a old trailer nearby ... i cleaned the blower assy and then removed mine the part # are not same the new one3500-590 has no capacitator old one 3500-6901does have capacitator. i have hooked all up and do have heat and ac however now the blower runs continuously.i have changed all the hardware inside control box with my known working the blower runs constant even when temp is reached THANKS AGAIN for ALL you do for members here!!! i will search forums again it seems a member had same issue and you walked him through then it magically repaired itself before he completed the tasks you asked himto perform hope i am that lucky .

3500-590 is a heat only blower, won't work for a/c use.

IF t-stat is set to auto and has 4 wires connected to it, then a sequencer or fan relay or a short is causing blower to stay on.


Thanks,
Robert

thanks for that info on the heat only blower ...i changed mine for the salvge one and will re install mine .id order a sequencer part 3120A3571...yes it arrived PROMTLY and I made a large mistake i had mark on the phone he gave me the correct part 3 which is 3115A3571 then i clicked the incorrect part # anyhow i again spoke with mark he told me that it will work! it controls 4 elements just the blower could come on at a different time than the correct one . i do question the ac thing as my compressor runs but also my elements are heating .so I have definately done something incorrect .sorry for the rambling post i have a lot on my plate as i am a trucker by profession. however i had a fire in my home and my insurance co was not very kind to me i took the morsel they gave me and am rebuilding my 91 fleetwood with very little knowledge but lots of great advice from friends who are in construction trade . so far so good i moved back in tonite after livng in a camper since june 17 . THANK YOU so much for your help in my quest to fix this unit i will put my original blower back in and the sequncer sent by ABERDEEN in morn and let you know what i get .

You're very welcome, happy to help.



Thanks,
Robert

the correct sequencer arrived today!! THANKS ABERDEEN ! i installed it ..all is well!! seems to be working correctly. just a note about the blower does work on both heat and ac . the parts person at aberdeen told me it is a smaller HP blowerso i will wait to see if it needs my old one reinstalled. after the fire i have gutted this trailer and put r13 in walls and r19 in cielings 1/2 in drywall and low e dbl pane windows .... THANK YOU ROBERT for ALL you do for us members of the forum!!!

Hi,

You're very welcome. As for the blower motor, it IS a heat only motor and does need to be replaced for a/c use.


Your choice whether to take the advice or not.



Thanks,
Robert