Weird Sound? No charge?

[Bryan]

Hey guys, today we took the bus out for a spin and had a new sound coming from the left dash area (pic below to show area) and it was like a rattling sound. If I was pressing the gas I would loose power the. The rattling would stop and I would have power again. It would only last a second or two. And it happened quite a few times weather I was pushing the gas or not. Also, anytime it rattled, the no charge light would come on (also see pic below) thanks for your help.

[zubzub]

this sounds like old bus stuff....open the wiring panel and see if something is lose.  troubleshooting is a long time in learning.......could be your master switch failing...don't know your bus so you need to start following wires etc...

[Cary and Don]

Relays can make a chattering sound when clicking on and off.  Resettable breakers will chatter if there is a problem or short. The two things are probably related.  Find the sound and you have found the circuit that has a problem. 

Don and Cary

[gumpy]

How was your air pressure? Sounds like a low air buzzer to me.

[B_K]

Could also be related to his other thread about trailer lights! If there is a wiring problem relays & breakers will kick in and out!
  BK 

[gumpy]

Wasn't there also a thread about  a knocking sound in the engine compartment a couple weeks ago?

[Lin]

Just being an armchair mechanic here, but Zub's post works for me.  I did once have a failing main switch and engine power would go off and on.  I do not remember if there was any relay noise, but it makes sense that the relay would chatter as it lost and regained power. So I would guess at the bad switch, a bad relay of a bad connection to either.

[Bryan]

hey guys! Thanks so much! Yes, you are correct I was the one with the odd engine knocking last week, and also the tail light voltage problem. The engine hasn't knocked since that day. But all of this could be related together. I haven't taken that side panel off yet where the dash chattering is to look behind it for issues. I suppose that will be my next step. I don't know to much what I'm looking for but I will for sure make sure all wires are in tact and go from there.

[gus]

There is a solenoid in that panel that clicks on/off when there is not enough load on the alt. Upper left as I recall.

The original alt is so big and a conversion load so small compared to a passenger bus the alt keeps turning on/off.

The solenoid keeps the AC/heat blower from operating when there is not enough output from the alt. When the original blower for AC/heat is on it won't click. Try it.

 I put a switch on mine, it drove me nuts. Now when I need heat I turn this switch on first, it is just a grounding switch for the solenoid.

[Bryan]

There is a solenoid in that panel that clicks on/off when there is not enough load on the alt. Upper left as I recall.

The original alt is so big and a conversion load so small compared to a passenger bus the alt keeps turning on/off.

The solenoid keeps the AC/heat blower from operating when there is not enough output from the alt. When the original blower for AC/heat is on it won't click. Try it.

 I put a switch on mine, it drove me nuts. Now when I need heat I turn this switch on first, it is just a grounding switch for the solenoid.

Are you referring to the switch labeled "Fan"? Just turn that on and see if it stops it.?

Speaking of heat, I'm not even certain the bus heat works, the PO said they used floor heaters in the winter. The ceiling A/C units put out great AC but not to much heat.

[gus]

There is a driver's fan switch.

The big blower is labeled Heat on the original, with your panel and mine it could be anything since neither is original! You can hear it run it is so big but originally it will only run with the alt on adequate output.

With so many conversion changes it could be wired any way but!!

[Bryan]

This is what mine looks like now. After looking at the manual, it appears that the generator ignition is over the original heater switch. Any suggestions?

[gus]

I had forgotten, there is a solenoid in the "engine run" circuit in the side elec comp. Open that panel and maybe you will be able to see/feel the noise maker.

[Bryan]

Ok so today the bus is no longer starting. It also made that same chatter while trying to start. We are pretty sure it is what I have pictures below which we think is the starter solenoid? Where can we find another one? Checked auto parts stores and they didn't have it.

[Nusa]

In general terms, a "starter solenoid" normally refers to the high current relay/switch that actually engages the starter, and would have hefty battery-like cables attached to it. It's nearly always in the engine compartment somewhere between the batteries and the starter. Often it's integrated with the starter assembly itself.

What you have there is more likely a relay. Given that your previous symptoms happened when the bus was already running, it's more likely something to do with the run circuit, not the start circuit. Can you trace where the wires from this relay went?  This is where you could really use the relevant manual pages for your bus, especially the circuit diagrams.

If you really need to move the bus, odds are the bus could still be started/stopped from the rear, assuming the original panels are still there.