COLEMAN MACH 15 AC PROBLEM

[andrews5]

SO MY COLEMAN MACH 15 AC IN MY CLASS C WILL NOT WORK ON COOL HIGH AND WHEN I SWITCH IT TO FAN ONLY IT WILL NOT WORK ALSO .IT WILL WORK FINE ON COOL LOW AND THE FURNACE WORKS .I REPLACED THE THEROMOSTAT BUT STILL SAME PROBLEM .SOMETIMES I CAN HEAR THE COMPRESSOR RUNNING ON HIGH BUT NO FAN .ANY THOUGHTS THANK YOU!

[dougrainer]

andrews5 wrote:
On our last trip a water bottle slid off the counter and spilled onto the entry steps and under those are the battery's and some other electrical stuff. My wife said that she heard a sizzling sound and on that trip is when we discovered that we had a no high fan . Could this be where the relays are located ?

NO. Doug

[andrews5]

On our last trip a water bottle slid off the counter and spilled onto the entry steps and under those are the battery's and some other electrical stuff. My wife said that she heard a sizzling sound and on that trip is when we discovered that we had a no high fan . Could this be where the relays are located ?

[wa8yxm]

The UPPER Control board refers to the board that is inside the A/C. .there may be two of them in there. Which is which is obvious.

Since everything in yours is controlled by 12 volts using relays. I'm guessing you have a bad relay.. Now... These are Easy to replace. if you can find someone willing to do it (I have two I need to replace in another device here when I get Round To It.

[haydenpage]

So the glh is not getting power it seems what should I check now ?

[dougrainer]

You just joined. ALWAYS Post Year and Model of RV. Post Model of appliance if you can find it. This helps tremendously in geting people help. Think of posting My Ford Explorer does not start with no info on the Car. See how hard it would be to try and get help:).
Odds are the Capacitors are good. They just "jump" start the motor. So, if the motor runs on LOW and you switch to HI, then usually the motor will go to Hi because it is already turning. Unless you have a 12 volt tstat supply problem. The HI tstat wire is not sending the HI run 12 volt signal to the upper board. You will see a GL(lo) and a GH(hi) on the upper control board. The wire to each will have 12 volts dc positive depending on LO or Hi selected. So, the FIRST thing is to see if the GH wire has 12 volts when Tstat selected for HI fan. If it does, then open up the control board cover and check for loose or burnt wires. DISCONNECT 120 BEFORE YOU DO THIS. Doug

[andrews5]

All wires look good and connected .
Could it be the Capacitaters

[dougrainer]

I assumed you have a wall tstat model? My advice was for Wall tstat controlled models. The Control board is mounted in front of the Evaporator on the metal front evap cover. If NO access from Inside then you have to go on top. The control board is located right above the Front of the inside lower access panel that holds the air filters. Doug

[dedmiston]

andrews5 wrote:
SO MY COLEMAN MACH 15 AC IN MY CLASS C WILL NOT WORK ON COOL HIGH AND WHEN I SWITCH IT TO FAN ONLY IT WILL NOT WORK ALSO .IT WILL WORK FINE ON COOL LOW AND THE FURNACE WORKS .I REPLACED THE THEROMOSTAT BUT STILL SAME PROBLEM .SOMETIMES I CAN HEAR THE COMPRESSOR RUNNING ON HIGH BUT NO FAN .ANY THOUGHTS THANK YOU!

Hi Andrew - Please don't post in all-caps. Thank you.

[andrews5]

where can i find the upper control board?

[dougrainer]

Odds are the HI fan tstat wire is not connected to the upper control board. Also, there is NO Hi compressor. Compressors operate at the same "speed" all the time. Just access the upper control board and you will probably see the hi fan speed wire spade pulled off the connection. Doug