Test Drove a 2005 Diplomat. ATC Dash light on & Brake (Parking?) light won’t go off

[Gazgreg]

What’s it designates? Test drive a 2005 Monaco Diplomat and it was on? Automatic traction control?

also park brake light wouldn’t go off?

[Tom Cherry]

Interesting.  More experts here on ATC  AUTOMATIC TRACTION CONTROL. Could be a faulty wheel sensor or, God Forbid, a major issue with the Data Buss.  That is a complex cable that connects all sorts of electronic devices….and has a special multiplexed data loop or 2 way communications and if all the devices aren’t happy or if one is upset(bad) or even a bad connection….  Suggest you google “Monaco Motor Home manuals”.  Use that link and download the 2005 Diplomat.  Go to the end.  There is an index.  Look up ATC  PROBABLY find a write up and description in the last section, CHASSIS.  Then read up on it.  Pretty straightforward.  

It, I believe, an EATON system….but don’t remember.

OK.  Brake light ON.  There is a Nassan (memory) switch UNDER the Parking Brake Air switch.  That switch has a few other functions.  On some, it sends out a “ground” signal to allow the slides to operate.  Sometimes, maybe, chit chatting with the aforementioned data buss, via the instrument cluster, and controlling the transmission.  

My personal opinion, but not all would agree…..they must be fixed by. Reputable shop.  Many times techs will tell a customer that it will be MEGA $$ or they can “cheat and bypass”.  We have had folks buy MH and find out that there was a bad dash instrument cluster.  No new one available.  If just repairing or replacing the Nassan switch (maybe $200 mostly labor..switch is cheap and common) fixes the Brake light….FINE.  

NOW…IF THERE is a BRAKE warning light and it is NOT the Parking Brake ON light, then all bets are off.

Read the manual.  Identify the two lights and read the description…..then don’t purchase until fixed….but be aware..must be a real fix.  The easy fix, which is BAD….locate the wire that turns that light on.  It is a ground signal so even a nicked wire can trigger….and cut it off.  No light don’t mean it was fixed.  This is done way more often than one would suspect….or maybe we see the consequences here.

[Gazgreg]

Wow Thank you Tom! Great info!!!!