Community Forums

ladagobago · 06-03-2018, 05:27 PM

What have you found to be the problem. I am having the same problem on a 7500. click but no start.

Budman55 · 06-10-2018, 06:49 AM

Quote:

Originally Posted by Budman55

I have an Onan 10HDCAA in my 2003 Monaco with just over 400 hours. It has always turned over. Had surging problems after I bought it because it sat for a long time with no exercise. That was all related to the fuel side. Rebuilt injectors, new fuel pump, and a new return line cured the surging issue.

Last week took it for a short run (about 150 Miles). Started the Onan to run the heat pumps to take the chill off and ran it for about a half hour. When I got back to base later in the day, I attempted to start the Generator but it would not turn over. I can hear the normal clicking from the glow plugs, but it doesn’t start. I get the service check code 3 and then a code 45 “speed sense loss after start” but the generator never started. Battery voltages on the house and chassis are both over 13.5 volts. No apparent power draw when try to start.

Any help would be appreciated.

Thanks to all who sent me ideas on how to resolve the “ no crank” issue on my 10K Onan.

What I found was a bad K2 relay. This is a small cube relay mounted under the top of the front cover. This relay is enabled by the generator control board after pre start sequence completes. The F2 fuse supplies 12VDC to the NO contact of K2. Once the K2 relay energizes, 12VDC is sent to motor starter solenoid. The starter for this 10K Onan is a combination solenoid/starter. The start signal from the K2 relay is a low current 12 VDC signal that enables the starter solenoid which enables the high current 12VDC to turn the starter motor.

When I removed K2, the relay was shot. The internal components of the relay had come apart and were loose inside the relay cube. This is what shorted out the F2 fuse and prevented the start signal getting to the starter solenoid.

Sorry for the long response but it was an unusual failure which was misleading.

Budman55 · 06-10-2018, 07:53 AM

Bad K2 relay.
The guts were loose inside the relay cube shorting out and blowing the F2 fuse. You may not have a fuse for the K2 relay depending on unit. You really need the schematic for your unit to see what is telling the generator motor to start.
Mine has an interposing relay (K2). The generator control board closes the K2 relay NO contact after prestart sequence completes. That’s what tells the starter to turn over. I got a replacement from Advance Auto for under 20 dollars.

Remove the wire from the NO contact on the K2 telay that goes to the starter while doing these checks.
Check with a volt meter that there is 12VDC present at the coil terminal of the K2 relay after prestart completes. Press the start switch, Check for 12VDC at the coil of the K2 relay. This confirms the control board is telling the K2 to energize.

Next, check that the K2 NO contact is closing. Press the stat button again. Check for 12volts on the NO contact of K2.

If 12 volts is present, the K2 May not be the culprit and you may have a starter issue. If the K2 doesn’t energize, check to see that the controller is sending 12 volts to energize the K2 relay. you may have a controller issue.

Check to see if your starter will turn over. This is how I did I it:
Disconnect chassis batteries (negative then positive) to do this safely. Disconnect the small wire from the K2 relay that goes to the starter solenoid (sta-con female blade connection). Attach a separate sta-con connector to this wire or use a small alligator clip test lead. This lead is used to send the start signal to the starter solenoid. Secure this lead to ensure not to ground to chassis. Reconnect chassis batteries (positive then negative).
Very important next step:
Keep your hands clear from any rotating parts. I used the 12VDC hot lead from the common side of K2 normally open contact .
Momentarily connect these wires. If the starter turns the engine over, your starter is okay. A couple revolutions is all you need to confirm the starter is okay.

Hope this helps.