12V Norcold control board connection

Hey John,
Think I really need some help from our Norcold experts.  My Recall Box has been clattering (clicking rapidly) anytime the outside temps get into the 80's so yesterday I decided to install an additional 12V Radio Shack cooling fan to blow up through the cooling coils, but when I connected it to the same wire the shop installed the Box in the 12V fan would not run.  (It do run when I connected it to my car battery.)  I checked the voltage at the in/out connections on the Box and found (if I'm reading my multimeter correct) that it measured .7 mv.  The meter dial is set to read DCV and the range was set to 200 mv so I'm assuming I read it right, never read any voltage that small. 

Can there be more than one 12V line going to the frig control board, and the shop may have hooked into the wrong 12V wire?  I can't see well enough in there
to tell what all the other wires are that are hooked to the control board but I do see 12V at the terminal where the Recall Box "out" wire goes to.

We just got back from an 8 day visit to relative with the coach and the frig worked just fine the whole time whether on 120V or LPG keeping inside temps in the 34-38 degrees set on #4.

This is getting more puzzeling as time goes on, and about run out of things to try in order to get rid of the clicking.  But it does help to leave the outside vent door off whenever temps get up there , which doesn't look very nice on a large DP.

Anyone have any help, suggestions, ideas, etc., other than calling Norcold which I've already done and just got a "take it to your dealer".  This response must be programmed into their telephone and ingrained in all trainees.  Too bad Norcold's CS can't be just a small bit the way Fantastic Fan Vent and HWH is in helping customers out of their problems.

Allen

Allen - you are better off talking to a brick than calling Norcold.  They are completely dealer-centric and want nothing to do with amateur RV technicians (no matter how skilled.)

We haven't had any recall done as yet on our 1200 4-door and I'm now wondering if that is a prudent thing to do .  I'm guessing here, but I think any Norcold mod doesn't involve running additional 12V wiring to the unit.  Sorry, but that's the best I have to offer!

12v motors are polarity sensitive. The fan should have two wires, a power and a ground. If you hook it up and it doesn't run, simply reversing the two connections should do it. A recall tech hooked my built in fans up to the board backwards. When I discovered months later the fans were running, swapping the connections at the board did the trick.

When they did the recall they didn't run any additional wiring.  They unplugged a wire from the control board, hooked that wire to the recall box "in post", then ran a wire from the "out post" of the recall box to the post on the control board where the original wire was removed.  Kind of put a Box in the middle of a wire to the control board to disconnect it when the box recognized an overheat situation thus turning off the frig.  But I figured that wire should at least be a full 12 volts.

Maybe someone out there has some experience with the hook-ups to the Norcold control board.

Allen

afchap said:

12v motors are polarity sensitive. The fan should have two wires, a power and a ground. If you hook it up and it doesn't run, simply reversing the two connections should do it. A recall tech hooked my built in fans up to the board backwards. When I discovered months later the fans were running, swapping the connections at the board did the trick.

Click to expand...

Polarity was correct, just not enough voltage.

Allen

I know this sounds elementary, but when you hear the clicking when the fan runs, take a mirror and look up (or down) into the fan and make sure that nothing is in the way of the blades.  It sounds like when the fan tries to turn on the blades may be sucking something into the fan.  It sounds silly, but it may be an issue. 

The wiring for the "recall box" varies depending on which circuit board your fridge has - there are at least three different ones.

Here is a source for the various wiring instructions for the recall box. Page through the 5 pages to see what matches yours:

Norcold Recall Box

I would wire the fan direct to the 12v source before it goes to either the fridge main circuit board or the "recall box".  Keep it out of the middle of things we don't fully understand/

One of the members on another forum e-mailed me the installation instructions that came with his recall installation (never thought to ask for mine when they did the job) which shows the 3 types of control boards, 2 new styles and 1 old style.  Mine being a 2004 turned out to be the old style, cover is held in place with 1 screw at upper left hand corner and 1 screw at each of the two lower corners.  His 12 volt hot wire was green, mine is yellow, which another member who had installed a Radio Shack fan said his was.

Anyway, the shop had hooked my box up to a black wire at the control board  and when I switched them around to use the yellow wire I now have 12V at the recall box posts instead of only mv,  the chattering has stopped, and I now can actually tell that  my coil cooling fans are running.

I've probably never had any protection at all during the last 2 months the way it was hooked up, which seemed to do nothing but keep my cooling fans from working.  Hate to call the shop and tell them they need to train their techs to read wiring diagrams but don't want to burn any bridges not knowing how well they would receive criticism like this.  If I hadn't walked by the side of the coach and heard the clicking I doubt I'd ever known anything was amiss.

Allen