tach acting up

[PaulC]

I have a 2004 motorhome on a 2003 W22 Workhorse chassis. On our last trip the tach started acting up. It will work fine for a while then all of a sudden it will drop to zero for a few seconds then bounce back up to where it is supposed to be. If I hit a bump in the road that will also tend to make it drop to zero then bounce back up. I checked the connections on the back of the instrument cluster and they seem to be seated securely. Any ideas?? Thanks in advance.

Paul

[PaulC]

I have a 2004 motorhome on a 2003 W22 Workhorse chassis. On our last trip the tach started acting up. It will work fine for a while then all of a sudden it will drop to zero for a few seconds then bounce back up to where it is supposed to be. If I hit a bump in the road that will also tend to make it drop to zero then bounce back up. I checked the connections on the back of the instrument cluster and they seem to be seated securely. Any ideas?? Thanks in advance.

Paul

[csgolfers]

I have a 2003 P-32 Chassis with the same problem. After checking for loose wires and grounds as advised by others, I decided to just poke around. I found that there is a "ribbon wire" running up the back of the instrument panel which fits over a couple of plastic pegs and that if I pushed that ribbon against the instrument panel, my tachometer stabilized and worked properly. I took a 4 X 4 piece of foam, wadded it up, and stuck it between the ribbon and the wiring in front of the speedometer so the ribbon was pushed against the instrument panel. I now have over 2000 miles on my "temporary" fix and the tachometer is still working. I don't know if it will work for you but it is a place to start.

[PaulC]

csgolfers,
Was that on the inside of the instrument cluster housing or on the back of it? I will go check it out and see if that takes care of it. Thanks for the response.

Paul

[csgolfers]

It is on the back. It actually is on the right side of the steering column even though the tach is on the left side.

[KenzRV]

Hey PaulC,
I have a 2004 Itasca Suncruiser 33', shorter than yours but basically the same coach with the SAME tach issue. But also, my check engine light (CEL) will sometimes "flicker" on and off. I'm sure your coach has the hinged dash/control center that mine has where you can pick up in order to access all the wiring etc under there. USUALLY, when the tach OR CEL starts acting up while driving, a little up and back down with the dash corrects it but only temporarily so it DOES seem like a loose connection some where.
csgolfers situation sounded like the same thing so today I charged out to the coach to look for the "ribbon" wire but, no such luck. Our Work Horse ACTIA dash must be different than what he has; the back of the ACTIA cluster has a black plastic cover with one harness plugged into the center. I have at various times also checked grounds and poked around but last trip out both issues reappeared on the way up, but all was fine on the way home.
So PaulC, did you ever get your tach problem resolved? Or does anyone else have any advice?
Thanx,
Ken

[KenzRV]

By the way
OK I had some time today so went back out to the coach for some more prodding & poking; I once again checked what grounds I could find (all were tight), then I propped the dash/control center in the up position, placed a mirror where I could watch the tach while I pulled/pushed/wiggled wires and harnesses and went at it. After about 5 minutes with the engine running I was about to give up then one more little tug and I saw the tach drop for a second! With a closer look I found some chafing on a wire loom and found a sharp area of an under dash metal structural piece. So I "rubbed" this chaffed area on the metal and was not only able to make the tach fail but the CEL flickered on as well!
After some electrical tape, zip ties, and minor re-routing, I am 90% sure I fixed BOTH of MY issues.
I hope this may help others.
Ken

[PaulC]

KenzRV,
Like you I checked the instrument cluster and could not find the ribbon cable that csgolfers mentioned. Next time I get a chance I will check for chafing and see if that could be the problem. Thanks for the info.
Paul