Instrument cluster quit working

[McFarlin AZ]

Hey all,

I recently changed all my house batteries in our 2005 Alfa Founder Edition 36FD DP. Now I have no dash instruments working. I have checked all under dash fuses and rechecked all the house battery connections.

All electrical services to the coach still work, Air, heat, receptacles, fridge and micro work great. Generator will start and charge.

In a nutshell only the dash instruments don't work. No fuel, air, temp, oil pressure etc readings. HELP!! I am at my wits end trying to figure this out and it is probably something simple.

Thanks and safe travels,

Mike and Cynda McFarlin along with three 4 legged copilots, Sadie, Toby and Cody. 2010 Jeep Wrangler toad. 2005 Alfa 36FD

[jerichorick]

Originally Posted by McFarlin AZ

Hey all,

I recently changed all my house batteries in our 2005 Alfa Founder Edition 36FD DP. Now I have no dash instruments working. I have checked all under dash fuses and rechecked all the house battery connections.

All electrical services to the coach still work, Air, heat, receptacles, fridge and micro work great. Generator will start and charge.

In a nutshell only the dash instruments don't work. No fuel, air, temp, oil pressure etc readings. HELP!! I am at my wits end trying to figure this out and it is probably something simple.

Thanks and safe travels,

Mike and Cynda McFarlin along with three 4 legged copilots, Sadie, Toby and Cody. 2010 Jeep Wrangler toad. 2005 Alfa 36FD

I am not familiar with the Alfa. What chassis are you on? You could call the chassis manufacturer seeking help. Your problem is a bummer. RV gremlins gots yea.

[Jim_HiTek]

Grab a piece of 14 Ga electrical wire and connect it from chassis ground somewhere near the dash to a ground lug on the dash.

[McFarlin AZ]

Jim,


I am on a Freightliner chassis. I haven't called them as yet. Hoping the good people like yourself could help me out before I give FL a call.


Thanks buddy

[McFarlin AZ]

Jim,


Do You suspect a ground issue and does the house batteries service dash instruments? I would have thought the chassis battery power from the ignition lit me up?

[McFarlin AZ]

Thanks Jericho,


Freightliner chassis. Haven't called them yet.

[Fred Cooper]

Freightliner used the System III instruments fed by a VDC (vehicle data computer) through most of 2004 and switched to the MMDC system for instruments in late 2004. You could have either of these on your coach.

Regardless, it appears that you have lost power to either the VDC or the MMDC unit (both are computers that drive the instruments). My VDC unit is located near the engine in a storage bay. The MMDC units are sometimes located in the front of the coach behind a console drawer. The location of these units is determined by the coach builder.

These computers would be powered from the chassis (cranking) batteries, so changing the house batteries should not have anything to do with the problem, unless a wire has been disconnected from the chassis batteries.

Freightliner supplies their chassis fuses in two (at least on my 2000 year coach) black boxes that are located by the builder of the motorhome. On my Freightliner, they are in the front driver side storage bay. The black boxes have snap on covers. The diagram showing what each fuse or relay controls is inside the snap on cover. I would suggest you find these fuse/relay boxes, remove the covers, and see if you can find a fuse or relay that controls the dash instruments, or that powers the VDC or MMDC. On my chassis, all of the relays are the same part number, so if you suspect a relay problem you can swap them around to see if the problem moves to the other circuit.

If no luck with that, get the last 6 digits of your vin number and call the Freightliner help desk (free service). (1-800-FTL-HELP) They can look up your wiring diagram for your chassis and provide some assistance in troubleshooting this problem.

Try to locate the fuse/relay boxes before calling Freightliner as I think they will have you checking fuses/relays in those boxes as part of the troubleshooting.

Good luck, and provide the solution when you have one.

Fred

[Jim_HiTek]

I think Fred's answer is a bit better than mine McFarlin_AZ. I didn't initially notice that you have a 2005. The dash losing a ground connection is what might cause it in older rigs, the symptom of all dash gauges losing power at the same time points to that. In a newer rig with SysIII instruments, you need to look a little deeper.

But it wouldn't hurt to look under the dash anyway. Many Class A rigs have a liftable dash cockpit console with fuses under it.

[Hooligan]

Here are 2 pubs on the System III and the MMC gauges, hope they help.
Both are pdf files

http://www.irv2.com/forums/attachmen...8&d=1399154181

http://www.rvtechlibrary.com/electro...mdc_owners.pdf

Neither system uses the house batteries for power.

[McFarlin AZ]

Thanks Fred,


After I get through all the info you and the rest of the great guy gave me I will let you all now!

[mchero]

LOVE to read thru these types of posts! Really comes in handy down the road if some of us others have the same issue.

I think the worst one is My Rig Wont Start! Soooo many relays & fuses on these FL chassis!

Thanks for the updates McFarlin

[gatorcq]

Go to this forum and request help in your question and I would also call the 24/7 Freightliner help line and/also Alfateers

https://groups.yahoo.com/neo/groups/alfaseeya/info

https://groups.yahoo.com/neo/groups/SeeYaDP/info

And you don't mention that you started the coach? How about the battery disconnect switch over the door?

[gatorcq]

By the way, check my signature -
President of the Alfa Roadrunner chapter

[ga traveler]

I would get a flashlight and look around the batteries to make sure you did not leave a lead disconnected. I have made lots of money from people who changed batteries and hooked them up wrong. Including a Pace Arrow that had a son install two 12 volt batteries in the place of two six volt batteries. (to the tune of $2,000) I know this is chassis part and you would not think they would run a chassis battery connection to a house battery, but I have seen some weird things in my 15 years as a service manager.