I have been fighting with my starter since I have owned the GMC. At first, it would occasionally go slow when it was hot but would always start. On our big trip last Summer we got stuck for a couple of hours while I jacked the coach up and re-tightened the electrical end of the solenoid because it had come loose and wouldn’t start. Some time later, when the starter was hot it would just not start at all – just turn the key and the dash lights would go out and there would be no noise whatsoever. This kept happening and on one trip I jacked the coach up at a gas pump and swapped the solenoid but still no joy. About an hour and a half after the problem began, it suddenly went away. This failure happened on several occasions and went away on its own each time.
In April 2011 we went to the GMCWS rally in King City, CA where one of the most knowledgeable GMCers (known in GMC circles as Mr. ERF) promised to help me solve the problem. Under his guidance I connected the battery cable directly to the starter – the rest of the electrical system was still routed through the battery shut-off switch and multiple connections – and replaced the ground cable to the engine because the battery connector was suspect. I also jumpered out the Park-Neutral Safety Switch (PNSS). I considered replacing the starter at this time but decided that I would rather know what the problem was – I don’t like throwing parts at a problem (my computer diagnostic background) but would rather solve it. The starter turned noticeably faster than it had but failed again on the way to Sacramento.
We left Sacramento after several days and headed to San Jose for another visit. We couldn’t pass through Fremont without stopping at Applied GMC for a visit – also had to deliver my recently replaced Rostra cruise control (thanks JimK). The starter failed again in the Applied GMC parking lot – perfect, now it would get fixed one way or another. I figured it would now have to be the starter and proceeded to buy a rebuilt from JimK at Applied and installed it myself – but, it did not fix the problem! I asked JimK for help and Alonso (we love Alonso) started to work on it. Using a schematic (what a concept!) he traced the problem to an open in the wire to the starter solenoid and found that I had my PNSS jumper on the wrong connectors – the starter problem is now gone. The newly rebuilt starter combined with the rewiring I did at the King City rally now sounds like a new car.
It turns out that the information on the GMC forum is mostly text and the photos that did exist were poor and didn’t help me. I had read that the switch was at or near the bottom of the steering column and easy to get to. Well, it turns out that the switch is just part of a larger multi-purpose switch that also contains the back-up light switch and another associated with the air suspension compressor. Without a lot of effort – you have to be “part snake” to get down there to work on it – it looks like the air suspension switch is the only one there because the rest of the switch is hidden behind the steering column. I decided to take some photos to post on the GMC photo site so that others might not make the same mistake as I did. Here they are:
The Passenger side of the switch
This is the part of the switch that I could see without a lot of effort. This is the wrong connector and has nothing to do with the starter.
The driver's side of the switch
This is the switch from the driver’s side where you can see the backup light switch connector and almost see the unconnected Park-Neutral Safety Switch lugs.
The driver's side of the switch - different view
This is a slightly different view of the switch with a clearer view of the PNSS connecting lugs – hard to see unless you are part snake.
The wire to the starter solenoid with a jumper.
The correct wires to the starter are purple and normally connected to the driver’s side of the switch. A well-made jumper on the correct connector solved my problem. Thanks Alonso.
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