For the last few months I've been dealing with very erratic performance of my analog voltmeter (VDO). Have changed alternator (cracked case), battery isolator (original - 20 years old), new coach batteries, cleaned all terminals, changed small relays on the battery isolator panel, etc. Voltmeter used to read just under 14 vdc either idling or traveling down the road. Lights, dash air, defroster didn't affect it. I can't remember how it first started but running voltage gradually dropped to 12.2 - 12.5 vdc and additional loads would cause periodic sudden drop to 10 - 11 vdc and speedometer (electronic) would reset to zero. Based on comments in the forum I decided to replace the ignition solenoid -Voila - problem solved and everything behaving normally again. At least for now :-)
John,
Where is it located?
Thanks,
Trent
Trent,
Different locations on different year coaches.
Suspect yours is just above the entrance steps in front of the passenger's seat-- need to remove the panel.
On many earlier model coaches located on the left side of the flip up dashboard.
On my 1995 U300 (build #4774) it was located at the bottom center of the circuit breaker panel - in front of the passengers seat. On my neighbors 1994 U300 it was directly in front of the driver - under the flip up dash.
Yes, Trent, ours are behind that panel on passenger side and they are black Bosch ones centre bottom as Jon said. Napa has them.
JohnH
Pictures of failed ignition solenoid.
Howdy Jon,
Great pictures of the failed solenoid.
Dave A
Jon, nothing really failed on solenoid that a bit of cleaning could not have fixed and put back together. Keep it as spare after done.
I have done this many times and back in service.
JohnH
Got to pick up some longer pop rivets and it will go into the "spares" drawer ;D
Hi Jon H;
I just bought a 1995 U 300 SE 3176 cat 6 speed like yours, Drove it back from Lemoore, CA to Hamilton, Mt roughly 1150 miles the coach ran beautifully ... Of course it's a Foretravel ... I digress , the original VDO voltage meter would go to the red/green zone with the headlights on and the light where dim and then for no reason at all it'd pop up to14+vdc the lights would brighten up then dim down again at random.... It a new to me coach and needs some TLC ...however, it always starts and runs fine ,so the alternator working... I was thinking voltage regulator or some relay.
Just saw your post and thought I might try the solenoid .... P s the batteries check out fine
Thank
Ckreider2
Ckreider2,
Welcome.
It could be nothing more than a dirty, corroded or loose connection. Check connections at back of alternator, battery isolator and batteries-- both positive and ground.
If symptoms persist, THEN start troubleshooting.
When mine did almost the same thing....... it was the voltage regulator. But..... be sure to check the battery sense wire connection on the back of the alternator and chassis battery connection point.
Assuming you have the battery sense style regulator.
Thank you the welcome and your advice...I'll check it out...
Really, rather than chasing all the "possibilities"-- and there are many, check all the connections. If that doesn't fix it, we can give you troubleshooting advice. That way you are not throwing parts at it, but actually diagnosing the root cause.
To troubleshoot, you will need a digital voltmeter (but, that is a mandatory tool on any RV).