Community Forums

jtdiscovery · 04-02-2020, 10:25 AM

I have a 2008 Discovery on a freightliner chassis and need help with my gauges. I can start it up today and the gauges may work fine for a few minutes and then maybe the tach will quit and the buzzer comes on, tomorrow may be a different gauge. Can anyone out there give me some idea where to start with figuring this out ?

AB7OH · 04-02-2020, 10:45 AM

Hello

I have a 2008 Forest River Charleston on a Freightliner chassis and it had a similar problem. They replace the LBCU and the gauges started working for a while and then they started working intermittently again, so then they change the wire harness to the gauges and that didn't fix the issue so then they found out that the volt gauge was the problem and it was replaced and now everything is fine. So what you should do is try unplugging one gauge at a time and see if the gauges start working regularly and if so you know that needs to be replaced. Good luck did.

mchero · 04-02-2020, 10:53 AM

You should open up the front of your dash and re-seat the cables . Also note if they are white or black in color.
I had an issue with my gauges not too long ago. I'd be driving down the road and all of a sudden the 2nd air gauge would suddenly drop to zero. The alarm would sound but after a couple seconds the gauge would pop back to normal pressure and the alarm would silence.
Called Freightliner giving them the last 6 of my vin and was told a new harness kit would correct the issue.
Ordered the kit and all back to normal after i swapped out the cables.
Original cables where white. New cables where black.

A digital signal is sent out the back of the LBCU. The cables distribute the data to the gauges. Is the lcd display on the dash working when you turn on the ignition?

I don't get where these "they will lie to you" stories come from. I have NEVER had an issue with Freightliner.

Pigman1 · 04-02-2020, 10:58 AM

Freightliner issued a service bulletin a while back on these type problems. I don't know if that's still active or not, but Freightliner would be the first place to check. Not a dealer, as some will lie to you and say the open service bulletin is no longer active (personal experience), so call the factory customer service. The dash gauges are all connected by a single wire and all the data is sent over that one line. Each gauge recognizes it's own data stream and pulls that off the line to display on it's own gauge. This is called multiplexing the data stream. The order that all the gauges receives that data doesn't matter. We had a similar problem on a 2008 Allegro Bus on a Freightliner chassis before the service bulletin was issued. I pulled the dash cluster out and and disconnected all the lines and jumpers from the gauges. All plugs are easy to remove, like a telephone line. I reconnected all the gauges back up mixing the plugs and lines in a new random order and never had the problem again. A quick, easy, cheap fix that may work for you. Give it a try if the service bulletin is no longer active. I think the service bulletin changed out the jumpers but am not sure. If this home made procedure doesn't work, I'd try it a couple of times. Also see if you can get a copy of the service bulletin and perhaps you can still order the jumpers. As I recall, the cost of Freightliner doing the update was expensive.

jtdiscovery · 04-03-2020, 06:47 AM

Quote:

Originally Posted by AB7OH

Hello

I have a 2008 Forest River Charleston on a Freightliner chassis and it had a similar problem. They replace the LBCU and the gauges started working for a while and then they started working intermittently again, so then they change the wire harness to the gauges and that didn't fix the issue so then they found out that the volt gauge was the problem and it was replaced and now everything is fine. So what you should do is try unplugging one gauge at a time and see if the gauges start working regularly and if so you know that needs to be replaced. Good luck did.

Thanks so much for your reply. I have unplugged all the gauges and plugged them back in but never tried unplugging them one at a time to see if the others start working. I will give that a try this weekend and hopefully I will find the culprit.

jtdiscovery · 04-03-2020, 07:32 AM

Thanks so much for your reply. I have checked mine and the wires are white. I have unplugged and plugged them back up but never tried unplugging them one at a time to see if I had a bad gauge. I never knew that the wires could be switched around and still deliver the correct signal to the gauge. I'll give it a try this weekend. Is the wiring harness very expensive or does Freightliner cover the cost since it was a bullenti ?

RichKimball · 04-03-2020, 08:37 AM

Quote:

Originally Posted by jtdiscovery

Thanks so much for your reply. I have checked mine and the wires are white. I have unplugged and plugged them back up but never tried unplugging them one at a time to see if I had a bad gauge. I never knew that the wires could be switched around and still deliver the correct signal to the gauge. I'll give it a try this weekend. Is the wiring harness very expensive or does Freightliner cover the cost since it was a bullenti ?

Definitely order the updated data harness black wires. I no longer have the part numbers, but if you call FCC in Gafney, SC parts dept with the last 6 of your VIN they not only can help with the pn but offer an excellent price as well.

Good luck. Even though I have changed the harness...and a LBCU....nothing has fixed my gauge issue completely. And I haven't been able to pin down a particular gauge that might be faulty either.

NCC-1701A · 04-03-2020, 06:18 PM

Here are the responses I got directly from FCCC Service. Part Numbers included. I had this issue a couple of years ago on my 2007 Journey. If I remember, I think I had an extra cable left over, but I got the whole set for something under $100. You may want to double check if these are the same for yours....I had sent an email to FCCC with my VIN on a Saturday evening and at 8AM Sunday morning I had the response. Another time on a weekend I had a response in under 2 hours by email. I've had nothing but exceptional service from the service guys in Gaffney.

As a side note, I originally took my rig to an Oasis center nearby and they charged me over $800 of time to not be able to find the problem at all and here the whole problem was in a service bulletin they should have been aware of, or if unsure, they could have contacted the mother ship and had the answer as quickly as I did. Never again. They refused to refund any of the charge.

Also, there is a document available online that has an entire LBCU diagnosis process that can help narrow down issues. You can easily do a lot of diagnosis yourself by following the flows of the diagnosis steps using the LBCU itself.

From your description it sounds like you have a connection issue with the Lin jumpers.
Look at the Lin jumpers (small wires) from the back of the LBCU (light bar) out to each gauge, if the color of these wires are white I would suggest you replace them.
Replacement part #'s:
A06-69135-012 QTY: 1
A06-69136-012 QTY: 6
POL 028A274098004 QTY: 2

A06-69135-012 has the feral it goes between the LBCU and the 1st gauge, A06-69136-012 jumper gauge to gauge the POL 028A274098004 (Y harnesses) are usually hooked to the air gauges.

Sincerely,
Gary Ramsey
Representative

NCC-1701A · 04-03-2020, 06:46 PM

I found the LBCU troubleshooting guide that I found to be extremely helpful. It ay be posted somewhere else on the forum already...not sure, so posting here.

Belgique · 04-04-2020, 06:41 AM

Same problem. Gaffney found that my temp gauge was bad. Replaced it and all is good.

jtdiscovery · 04-05-2020, 06:42 PM

Quote:

Originally Posted by Belgique

Same problem. Gaffney found that my temp gauge was bad. Replaced it and all is good.

Has your white wiring harness already been replaced? Thank you so much for sharing your info with me. You RVers are the best.

Belgique · 04-06-2020, 06:28 AM

No, it had not been and they did not change it when they put in the new gauge. I trust Gaffney completly so I didn't say anything. Several thousand miles since then and no problem.

jtdiscovery · 04-07-2020, 05:47 AM

Quote:

Originally Posted by Belgique

No, it had not been and they did not change it when they put in the new gauge. I trust Gaffney completly so I didn't say anything. Several thousand miles since then and no problem.

Are the gauges very expensive ?