Instrument cluster dead

[Flyboy01]

I have a 2018 Tiffin Phaeton on a Freightliner chassis. A couple of weeks ago the instrument cluster froze. The speedometer stuck at 62mph, the tack froze, the fuel gauge froze and the air gauges dropped to zero. After I stopped the coach, shut down the engine and restarted it, things returned to normal. I called the dealer, who suggested that there might be a loose ground or loose relay. I found a loose relay that I thought might be the culprit and pushed it back in.

I used the coach on a short trip with no problems.


Unfortunately, the problem has returned. This time the speedometer jumped to full deflection and then returned to the speed I was doing and stuck there. I then noticed that the air pressure, battery, fuel all read zero. The tach and speedometer were stuck at 62mph and 1700 rpm. I have rechecked the bus bars and relays and fuses, but can’t find anything loose.

Can anyone think of something that I can check, or any suggestions on what the problem might be.

Many thanks

[Tommo nz]

I and many others have the same problem. Mine is a 2007 Damon on a F/L chassis. I took the motor home to a Freightliner service center but they could not fix the problem After talking to Freightliner custom chassis I purchased up graded jumper cables and fitted them. From that point on the gauges started to work with intermittent shut downs. Then it poured down while travelling and once again they shut down for several hundred miles. I am going to start with checking for any loose electrical connections and apply di-electric grease.

[markmiiler]

I have the same issue what did you find to be the problem tommo

[Roadwarrior7]

Tommo posted:
"I purchased up graded jumper cables and fitted them."

You must mean that you upgraded your battery cables?

[kya]

I think he means the wires on the back of the gauges . freightliner daisy chains the gauges , they updated the wires to help solve this problem, it did not work on mine. They ended up replacing the LBCU unit and it worked for a trip out west then they stopped working again.. its going back into the repair facility again after thanksgiving... its a real pain in the A--.. when mine go out the only thing that works is the air pressure gauge.. the LBCU stays working so I can monitor vitals of engine & speed.. JUST no fuel gauge which make s thing a might interesting. my unit is a 2009 Freightliner chassis. coachman pathfinder DP.

[rexandrose]

What is a LBCU?

[dp7]

Originally Posted by rexandrose

What is a LBCU?

Light Bar Control Unit.

[Flyboy01]

Originally Posted by Tommo nz

I and many others have the same problem. Mine is a 2007 Damon on a F/L chassis. I took the motor home to a Freightliner service center but they could not fix the problem After talking to Freightliner custom chassis I purchased up graded jumper cables and fitted them. From that point on the gauges started to work with intermittent shut downs. Then it poured down while travelling and once again they shut down for several hundred miles. I am going to start with checking for any loose electrical connections and apply di-electric grease.

In the end, it turned out to be a loose ground on a bus bar.

[txcpl]

WE had a similar problem, and it too was a poor connection. Glad your problem is fixed.

[Dfreiberger]

Mine went dead as well. I cycled off both the chassis and coach master power switches off for about three minutes and back on. All is good now for the last 6 months

[Dsmulloy]

I have a 2018 fleetwood with the same issues. I disconnect each of the instruments, sprayed the connections with cleaner and reconnected them. They appear to be working. I would be interested in any other updates

[PacificaDen]

Originally Posted by Flyboy01

In the end, it turned out to be a loose ground on a bus bar.

My unit is a 2008 National Pacifica with Freightliner chassis. The LBCU, lightbar in the speedometer is my backup speedometer and tachometer.

I get this really strong vibe that my problem, which is mimicked over and over by the replies and descriptions in this thread, that the main problem is a ground somewhere.

Flyboy, where is this bus bar and where on it is the ground?????

THANKS TO ALL OF YOU FOR YOUR DESCRIPTIONS AND THOUGHTS

[Toribk]

It might be the connections or the MMDC (Multi Module Data Computer) itself.

On my unit, the module is mounted on the inside firewall left of the steering column. It is grounded to a bus bar directly behind the steering column.

Attached is a generic photo of what your looking for. Check to make sure the big chassis wiring harness pin connections are clean and tight.

With 2018, you should have the black daisy chained wiring for your instruments which were problematic in earlier years. Still, check and make sure connections on the back of the instrument panel are free of corrosion and secure.

[Flyboy01]

Originally Posted by PacificaDen

My unit is a 2008 National Pacifica with Freightliner chassis. The LBCU, lightbar in the speedometer is my backup speedometer and tachometer.

I get this really strong vibe that my problem, which is mimicked over and over by the replies and descriptions in this thread, that the main problem is a ground somewhere.

Flyboy, where is this bus bar and where on it is the ground?????

THANKS TO ALL OF YOU FOR YOUR DESCRIPTIONS AND THOUGHTS

Hi there,

I have the Tiffin Phaeton and when the generator slide is open, you can look in there. On the back wall there are a couple of mettle bus bars with screws going through them to hold wires in place. A couple had worked there way loose, so I tightened them. That fixed the problem for a while. The problem returned though. I noticed that the gauges would lock up when I had been driving for a while with the dash AC on full. It turned out that there was condensation that would form on the lines that route the cold air to the eye ball outlets and would drip onto the wiring causing it to short. I rerouted the ducting and insulated it too. That was years ago and I haven't had a problem since.