Community Forums

Phoelix · 12-19-2017, 06:47 AM

Why do relays “click”? My 1992 Chevy chassis Onan generator relay just clicks when I try to start it by the dashboard switch or the remote switch on the generator itself. Plugging in 120vac from the house makes no difference.
Both batteries charging with house switch selected on (13+ VDC). Both batteries freshly charged, all connections tight. When I start the main engine, the generator starts strongly and from both switches. NEED A DIAGRAM,,,

Wroughtnharv · 12-19-2017, 09:53 AM

First I would look at the coach battery for a weak cell. It can read 13.4 and still be weak when load is put on it. I would watch a voltmeter to see what happens when you hit the starter. If the voltage drops then it's the battery and they can be tested at any parts store. Always change batteries out as a set.

What is happening it sounds like to me is the coach battery is bad and can't handle the load of the starter. But when you have the engine running the voltage is strong because you have the current from the engine alternator.

As for a diagram, don't search for specific manufacturer or model. The circuits are pretty well generic, especially with the older coaches.

twinboat · 12-19-2017, 09:58 AM

Did you remove the house battery terminals and clean them or just look.

The corrosion often can not be seen.

When the engine is running, the chassis battery ties into the house battery. That's why it starts.

If you make it click a few times, the bad connection will feel warmer the the others.

Phoelix · 12-19-2017, 12:30 PM

Swapped batteries, no change. Main engine starts with either battery, but with engine off, neither switch will produce more than a clicking generator starter relay. When I plug my extension cord into the MH, and turn the house switch underneath the drivers seat to the ON position, the clicking is much healthier and louder.
I see two relays mounted onto the firewall, and trying to figure out where the wires go, what they're for, or even which battery is which is proving to overwhelm me. The left battery I assumed was the house battery, as it was receiving 13.6 vdc when the house power is turned on (engine off), the other battery at 12.6, but when I disconnect the one being charged, the main engine won't turn....
When I run a jumper from the battery to one of the relays on the firewall, it makes a distinctive "click" sound, then generator starts right up with no clicking when either start switch is pushed. I imagine one of the firewall relays is the "start assist" relay that is actuated by the start assist switch, but it does nothing either, nor has 12 volts when the start assist switch is pushed (my next endeavor).
So I guess my question would be what is the purpose of these firewall relays? I kind of understand the assist relay for engine starting, but not sure of the purpose of the other relay that starts my generator when jumped. Haven't been able to find an even simple diagram of the generator starting circuit, and I can't understand why that one firewall relay would have to have power to it all the time in order to "ARM" the starting switches.
Tried following the wire that comes off the mysterious relay, it goes up behind the dashboard. Manually feeling it, a connector fell off that was poorly crimped from somewhere. Ran out of time.....

RKins · 12-19-2017, 12:40 PM

Could you be having the same problem as this thread? Read it all the way through.
http://www.irv2.com/forums/f103/8kw-...ar-371667.html

YC1 · 12-19-2017, 02:51 PM

How long have you owned this RV? If it is new to you and are dealing with a diesel generator you may just be impatient.

If you have had it for some time then one of the solenoids may be either your "salesman" switch solenoid and might need to be engaged to supply power down the line.

The relay that you jumpered may be bad. Can't quite determine with your well thought out description.

Grab a voltmeter and measure the large posts of it. Then have someone push the switch. See what the voltage is on each side.

IF the voltage holds around 12 on one side and you get virtually nothing on the other side it is bad. If the voltage on the large posts both go low then you have a bad feed line or connection and you need to trace that line.

Magnafique · 12-19-2017, 05:47 PM

My battery disconnect switch clicked just fine, however it was not making a connection, so I changed the solenoid and it works fine for the batteries. Perhaps your solenoid for the generator/aux battery switch is no good. Just a weak hunch

Phoelix · 12-19-2017, 07:18 PM

I’ve owned the rig since August....I’ve already had the generator removed and in my garage for a starter replacement. It’s definitely a gasser...The generator has always started right up.
While manually tracing the wire that powers that relay, a poorly crimped splice fell to the floor. Ran out of time, had to go to work...I’ll figure it out, and let y’all know....