81 Diesel Glow Plug question

[Lars Kneller 8246]

My 81 Fleetwood diesel glow plugs are acting up. This morning I turned the key to "ON" and the WAIT light stayed on and didn't go off, and the engine wouldn't start. The glow plugs weren't lighting up. After turning it on and off several times, they finally heated up, the WAIT light turned off, and the engine started with no problems. Also, recently after the engine starts, the WAIT light will come on briefly then turn off. My question is, does this sound like a faulty glow plug relay?  This seems more likely than the glow plug controller. Thanks for your help.

[TJ Hopland]

If its got the correct glow plugs in it and they were on for more than about 30 seconds they would now all be dead.   I would have to refresh my memory on how that whole mess worked.   There is a relay on the firewall that operates the light so the light being on does not for sure mean the plugs are actually glowing.  The controller sends the signal to the solenoid and there is also a feedback to the controller so it knows the plugs were actually getting power.  I would start checking grounds.   I believe there is a ground wire that grounds the wait relay and possibly the fast idle relay.    I think the solenoid has a ground wire also.   Maybe also have a look at your battery cables and the connections on the solenoid.   The stacked battery cables are a good place for corrosion so take them apart and make sure things are good and clean between them.    Post back if it does it again and I will pull out an 81 book and make sure its the same as my 80 that I am familiar with.