WILDSIDE

Same issue with me. Primary issue was with the gnd stud under the battery. It had rust between the bolt and the negative battery connection. I took a wire wheel to it and other connections to clean it up and I'm all good now!

Hey y'all, Just a quick note to let you know that the genny is running. It had to be a combo of a poor gnd and a weak battery. Charging the batteries and cleaning every battery terminal, connection, and gnd stud restored the genset to full operational condition! Thanks for all your suggestions and in depth detail of the solenoids. Dean

What's a hot cable? Are you referring to the positive side of the 12V ckt?

I took the batteries in and both checked out good under load. I had to order the battery cables as my salvage yard had a clean out and no longer carries cables. They should be here early next week. I'll use my jumper cables to continue troubleshooting what I am accepting as a ground issue. I'll focus on terminations and closer inspect the battery cables between batteries, the frame gnd, and the genset gnd.

Both of the two small posts are unmarked. Both are open between the frame and post. The 4Ω measurement is only between the two small posts that are not labeled as S or I.

I tested the solenoid this a.m. with it mounted in a vice which is isolated from ground - its mounted to a wooden bench... I connected the positive 12V from the positive battery terminal to the input terminal and the negative battery terminal to the frame / mounting point / vice. I then grounded the right small post (don't know if it is the I or S post) to the same potential as the negative battery connection. When a ground (same potential as negative terminal) on the left small terminal, nothing happened. Then I applied 12.3VDC to the left small post and measured 11.9 - 12.1V at the starter terminal of the solenoid. I'm curious to the cause of the voltage drop... I removed the ground from the right small post and applied 12.3VDC to the right small post and measured 11.9 - 12.1V. I'm still curious as to the 0.2 - 0.4VDC drop... This is what I measured: 1. 4Ω between the two small posts 2. O.L between batt post and starter post with nothing terminated to the small posts 3. 12.3V on the batt between the + and - terminals 4. 11.9 - 12.1VDC with a ground on either small post and 12.3VDC applied to either of the opposite small posts Observations 1. With S grounded and 12VDC applied to I, the post that is not grounded, the solenoid relay closes and allows voltage on the starter terminal and current to flow to the starter. I don't know which post is S or I so I conducted the same test and swapped + and - and observed the same indications when the opposite post was grounded and 12V was applied to the other post. 2. Nothing happens if both S and I posts are grounded 3. Nothing happens if both S and I posts are tied to 12V. 4. I tested both the original and replacement (OEM) solenoids and observed the same measurements and voltage drop with a ground on either post and 12V on the opposite post. Take aways: 1. Both the original and replacement solenoids provide similar results. 2. Both solenoids appear to be operational - taking into consideration the voltage drop as being acceptable. Assumptions 1. I have a ground related issue on my trailer that is impacting the genset 12v circuit. 2. Batteries are still suspect and will be tested today.

I measured 4Ω between the two tabs on both the original and OEM replacement solenoid.

oldjohnt, Kirk W, Ray,IN, and rickeieio, Thank you for all of y'alls suggestions. Thanks oldjohnt for the write up on the Ford type and non Ford type of solenoids. Kirk W thanks for the diagram. Both posts were highly informative. I'll see if I can get the solenoid to actuate using jumpers and one of my batteries from my charging station. My plan is to bypass the RV (toyhauler) wiring and go from the existing batteries to the solenoid like what I did with the jump battery that previously turned over the genset. Then I'll see if I can half step it and add parts of the existing wiring until I can identify the ground / voltage drop issue. I'll swing by O'reilly's and have them load test the original batts Saturday morning when I pick up the cabling at the salvage yard. They've got battery cabling by the spools. I love that place... Do y'all know where I can get wiring diagrams of the trailers 12V and 120V systems? rickeieio - I'm running two batteries (875cca) in parallel. These run the 12VDC circuits such as the lighting, radio, water pump, heater blower and fridge as well as provide the spark for the genset. The internal 12VDC circuits are fully operational and battery drain is what I've come to expect which is that the batteries will run the heater fan all night in the 30° SoCal desert and still crank my extremely loud, yet operational 8KW genny that I've been hauling around with me this winter... So batteries may not be the issue... I've got a bit of electrical experience but that was mainly with shipboard power which was 3 phase and 400Hz and checking continuity on various types of cabling. I do recall DC circuits from BEE(p) school... chasing grounds regardless of current type is a challenge. Thanks for reminding me of the importance of having minimal resistance - especially with grounds. The whole frame is a common ground. Continuity on this short of a run (frame ground front of the trailer to frame ground at rear) should be less than an ohm. The 30Ω reading from the genset gnd to the ground stud is excessive. I see that now. I apparently didn't clean the frame stud well enough. Either that or I have a combination of what some of you have mentioned; multiple gnd related issues. I'll inspect the battery terminals and cabling for corrosion and look under the insulation for hidden corrosion. It might be time to replace the battery cables again. Kirk - As I understand it, the solenoid is grounded to the frame at the bolting point. The S contact is the ignition switch. The opposite terminal of the battery connection (12.6 - 14VDC) goes to the starter. Does the I contact and starter terminal voltage levels remain at 0VDC until the S contact receives 12VDC? Once the genset starts running, the S level goes to 0VDC as I've released the start sw. What happens to the voltage on the I and the starter terminal when the S post returns to 0VDC? I would expect that the I post would remain hot as it provides the battery voltage to the ignition coil but the starter post would go to 0VDC as I don't believe the starter would remain engaged with the fly wheel while the motor is running. Does the I contact stay hot until the kill (gnd?) signal is received? Is the kill signal generated from the processor board? Is it as simple as closing a ground on the ignition coil? I'll y'all know what I find this weekend. I want to get this fixed so I am not out at the "self-imposed" outer ring of the camping circle next weekend due my periodically running of my behemoth 8KW genny...

I have a 2008 Onan 4KY version K 33amp 120 Hz GenSet that will not turn over. Indications are that the solenoid will activate when pushing the local start switch and after about two - three seconds of activating (clicking), the solenoid stops. A measurement of the battery measured 3VDC and the solenoid does nothing. But then, almost like a charging capacitor, the battery voltage increases back to 12.5VDC. I have to disconnect the positive lead from the solenoid to reset the solenoid. At the start of it, the battery measures 12.9VDC at the solenoid battery stud. Resistance between GenSet ground and negative battery post read 250 Megaohm so I cleaned the ground stud that's welded to the camper frame and now resistance measures 30 ohms. The GenSet ground is clean. I replaced the solenoid with an OEM solenoid and have the same indications. I connected an external battery to the ground and starter lead and the GenSet will crank. I dont know if the GenSet will shutoff when the battery is disconnected so I did not continue to see if the GenSet would actually start. By the way, which contact is the "I" and which is the "S" on the 307-2586 solenoid? Picture attached... Any troubleshooting suggestions?