10 wire thermostat

Rhaduznt · 08-18-2024, 10:33 AM

I have a roof top dometic a/c unit model 58915 306. Anyone know what each wire is for?

**JohnB** · 08-20-2024, 05:04 PM

Hi Rhaduznt,

I tried to look up a 58915 roof unit but could not find an AC unit in the 589 series.

I have worked on many of the 579 series, which are the older Brisk Air models. A 57915 is a number I can identify with.

I'm not the old Dometic wizard on all their part numbers, but did you have a typo on the 58915? There may be one, I can't find it to help better.

You also mentioned the 10-wire T stat; from my understanding, the roof unit only has a 6-wire plug that plugs into a "control box". The control system to run the roof unit can have several different style control boxes to run the same roof unit. The T stat communicates with the control box, not directly with the roof unit. So, only knowing the roof unit part number will not help find the T stat control.

Somewhere on the side of your control box is a long Domeitic part number that is very different than the roof unit. The T stat also has its own part number.

See if you can find the part numbers of all 3 pieces.

Could you post pictures of the system, if possible? I know you are on a quest to know what the 10 wires are for, and Dometic does make a 10-wire cable, but I need more info to go on. Is yours broken? If so, what does and does not work?

Is the AC system on an RV? If so, what is the make, model, and year? That may help, too.

Hope this helps

John

Rhaduznt · 08-20-2024, 09:41 PM

That is the part number of the roof top unit. It quit working and was acting like it was a t stat problem so I was trying to find another one that would work that didn't cos $250. In the process, I have misplaced the old t stat and don't know the part number. I have figured out the roof top unit provides the 12v to operate the t stat and that may have been the problem. There is a 10 wire cable running from the roof top unit to the t stat but no one seems to be able to tell me what each wire does. Google doesn't even know.

krazedave · 08-22-2024, 05:29 PM

The year of your trailer would be helpful. The late years Sunlines used a Dometic t stat model #3106995.032. They had their problems but that had to do with the furnace operation. The fix was a new t stat, wiring harness and control box. I am not sure how many wires though. Does your a/c unit have a heat strip?

Dave

Rhaduznt · 08-23-2024, 09:28 AM

The trailer is a 1993 Shasta. No heat, just a/c.It is hard to believe I am the only one with a 10 wire setup.

krazedave · 08-23-2024, 05:33 PM

A picture of your wiring coming out of the wall and the plug at the control box might help with solving the mystery. I know that I am not the only retired or working tech on here.

Dave

**JohnB** · 08-23-2024, 09:15 PM

Quote:

Originally Posted by Rhaduznt

The trailer is a 1993 Shasta. No heat, just a/c.It is hard to believe I am the only one with a 10 wire setup.

Hi,

I searched for some more information, but I cannot find a manual or service manual for model 58915 306. However, I found a used rooftop model, 58915.305, which is a very old unit. I'm unsure of the difference between the .305 and the .306, but I suspect there is not much difference to try and help you.

This dealer is selling a used AC unit, and it has a 10-wire ribbon cable connection, and the rooftop unit control box is very large compared to the 579 series that many of the Sunline campers use.

Does your roof unit look like this? There are many good pics of the unit. https://youngfartsrvparts.ca/product...-btu-cool-only

If that is your unit, it helps us know more about what you have.

If you cannot get the older controls to work or get parts, I may have an option if you can get 12 VDC up to the AC unit. You do not need a lot of 12 VDC, 1 -2 amps will work. A picture inside the control box would be helpful so we can see what you have to work with. And there may be a wiring diagram on the inside of the cover, which can also help. That old system most likely had a power transformer inside the control box to create its own voltage source to run the T stat.

If the compressor and fan are still operating and you have electrical skills, you can change the control system to a more modern control box and capacitance touch T stat with parts available. I have done this twice when the parts are no longer available on the 579 series AC units, using Dometic 3316230.700 Control Kit/Relay Box Heat/Cool with Polar White CT Wall Thermostat. The control box applies power to the compressor and fan from the T stat, and it has a frost control feature. You only need three wires from the control box to the T stat; since you have 10 wires, you would only need 3 of them. If we can see inside your control box, we can see if this option will work. This option would be about $140 plus tax. here is one seller. https://www.amazon.com/Dometic-Air-C.../dp/B086RQ5LNM

Hope this helps,

John

**JohnB** · 08-23-2024, 09:17 PM

If you need help posting pics, here are the basics.

There are three ways to add pics.

1. Upload pics to a specific post, attaching them at the end of the post.

2. Link them in from a publicly viewable web photo hosting service you have.

See here for 1 and 2 https://www.sunlineclub.com/forums/f...html#post86041

3. You can upload pics to the forum in your own personal photo album. Then, link them anywhere in the text of a post. See here on how to create an album. https://www.sunlineclub.com/forums/f...html#post87945

If you still need help, let us know. Pic's go a long way in helping show things you are working on.

Hope this helps

John