GE Fridge defrost issue?

[Ronyeager]

Okay so my last customer had this pretty nice GE she was replacing with an Amana that I had.  I took the GE off her hands.  I noticed right away that there was frost everywhere inside the back of the freezer.  I can do some basic testing and determine, with your help of course, what the defrost problem is.  However, this unit does have a main board.  I do not even want to mess with the fridge without being able to tell if the main board is bad first.  The fridge seems to work just fine right now, it's getting cold and cooling both sides.  I assume that means the main board is in good shape?

Model GSS25JFMCWW

[tgoods]

There's a quick way to check the defrost system at the main board.  Find the main power connection, it's the molex plug with three spade terminals close together.  Connect a jumper wire between power and def.  Check for an amp draw. You have an ammeter, right? Okay, if you don't have an ammeter, get one.  If you still don't have an ammeter, look for a spark when you disconnect the jumper wire.  If there's no spark or amperage, either the heater or defrost thermostat is bad.  If there is amperage, you have a bad evaporator thermistor or main board. Thermistors can be checked at the main board. Here's a cheat sheet with thermistor values.  In my experience if a thermistor is bad it will show way out off spec, like showing 120° in a 0° freezer.

[Ronyeager]

does the jumper wire need to be anything fancy?  Also, I do not have an ammeter, I just never needed one and I am in the beginning stages of repair.  Would I have a lot of use for one?

[JWWebster]

Ron I have an older ammeter. Give me yer address and its yers dude.

[Ronyeager]

That sounds awesome, thanks JW.  I sent you my address and phone number.  thanks!

[JWWebster]

Got it. Now if I can come up with slow boat to AZ postage money. LOL

[JWWebster]

OK here is what I am going to send ya  
As seen on eBay New never used no instructions included.
Click on pics to enlarge:

[Ronyeager]

Well, it looks like I am going to have some fun! 

So on this GE fridge, it has been plugged in for 24 hours and the top 2 evap coils are not getting cold or frosting up.  Does that mean low on freon?  Or is the thermistor just not doing it's job?  I was thinking about just replacing the thermistor to see if it does the trick while I wait for the ammeter, good idea or bad idea?

[JWWebster]

You should get the meter in about a week. Spent about $8 at the PO for slow boat postage.

[rego]

It's been my experiance with no frost/cold in a portion of the evap. coils the cooling system is low and needs a charge.  Unless you have a buddy who does HVAC and will give a break on checking it can be to expensive for the fix.

[Ronyeager]

Pretty proud of myself on this unit.  I was able to determine that the units circuit board was working properly, but, the unit needed a recharge.  So I went on craigslist and to my luck I found a GE profile unit that is much nicer than this other GE. The only problem with the Profile was the circuit board was bad, I picked that unit up for free and changed out the circuit board from the other GE I had and came back this morning and it was freezing and cooling like a champ!  Both units were free so I made out nicely on this job.  Thanks for everyones help, thanks JW!

[JWWebster]