What is wrong with this Freightliner....quiz..

[mwilson]

Truck equipped with ParkSmart driver comfort system which provides heat and a/c for the sleeper berth when truck is parked and shutdown...accomplished with the use of an Espar D2 air heater and 4 extra batteries to run a 12v compressor for the closed a/c system...

Complaint is truck refuses to shift over to a/c mode, remains in heat mode no matter what the in cab setting is...truck currently in our shop...

Answer is in this screen shot, if you get it right off quick hold back a little to see if others figure it out....

 

[GCroyle]

Ok I’ve got my hunch.

 

[TFucili]

Mike, can we ASS-ume the top line voltage warning is because it's key on, engine off?

 

[AEdelheit]

Pretty sure I got it....

 

[mwilson]

Mike, can we ASS-ume the top line voltage warning is because it's key on, engine off?

Yes, truck batteries (4) are at 12 volt due to key on, engine not running.

ParkSmart batteries (4 more!) are at 12.25..

 

[JR]

ParkSmart batteries (4 more!) are at 12.25..

Ruh Roh!

 

[mweiman]

Pretty sure it’s not that cold in Maine.

 

[TFucili]

BTW, what do we win, Mike???

 

[mwilson]

..

 

[mwilson]

Pretty sure it’s not that cold in Maine.

It's certainly not that cold in my Thermoking bay.....

 

[mwilson]

BTW, what do we win, Mike???

The extreme satisfaction that you guys know as much, if not more about these electronic nightmares then we do.......

 

[mwilson]

This truck has been a frequent flyer for this issue, even though the ParkSmart is an integrated option communicating through the BUS the info is hard to find...

Thought we had it pinned down once we found that sensor thinking it was close to -20, but now think the ParkSmart control board is toast....it's not reacting to the signal voltage that the sensor is returning....so no a/c action.....

 

[GCroyle]

That -18.2 caught my attention

 

[mweiman]

I was going to ask how big of a nightmare diagnosing it has been.

 

[Dan_69GTX]

So why are the batteries low - lack of runtime, malfunctioning charging system? Is there an isolator between the 2 battery banks to prevent truck batteries from being run down (provided the key wasn't left on).

 

[mwilson]

I was going to ask how big of a nightmare diagnosing it has been.

This is the first deep dive into a ParkSmart that is out of warranty. While under warranty they just shipped out entire replacement units.....so this is the painful one. After this one it won't be so bad....

A lot of the current labor charges on this puppy will go to training, that's how it goes sometimes in the interest of fair play.....

Our T/K whiz is on this one, he knows the Thermoking TriPacs inside and out...this however is a whole different kinda animal....

 

[mwilson]

So why are the batteries low - lack of runtime, malfunctioning charging system? Is there an isolator between the 2 battery banks to prevent truck batteries from being run down (provided the key wasn't left on).

It's a combination of key on for testing plus the truck may not have been through the 8 hour run time required to return the ParkSmart batteries back to a full state of charge....there is usually an LVD (Low Voltage Disconnect) programmed into the truck, it appears that a second threshold can be set for the ParkSmart if desired.

In my opinion the ParkSmart style units are only good for a dedicated run, for example the truck stops for 8 hours only and then boogies up the highway for another 10 hours or so....not for two days stranded at a truck stop or not while powering an inverter, microwave, electric blanket, TV, coffee, etc....

That's why I favor the TriPac units with the 2 cyl Yanmar diesel, indefinite run times using very little fuel...

 

[JR]

Is the 12.2 volts an accurate reading

So why are the batteries low - ).

I would have thought for sure this was at least pointing to the problem, even the remote pack setting at 12.2 volts is only 50% charged. That would be enough to cause some gremlins in most any modern system now a days.

 

[mwilson]

I think they will go as low as 11 volts, they are AGM and being pulled way down is the nature of that system. Sometimes if it’s hot during sleeper berth time they won’t even make 6 hours I have heard..

 

[Wayne M.]

Mike, what’s the FCU volts and the ISO triangle?
Regarding the condenser temp, there should be a reference to test the sensor via DVOM, and if that’s reasonable, there could be a harness issue or worse like you are thinking.