M-818 pre heater problem

[g102]

The preheater on my m818 doesn't work. If the spark plug is bad will this cause the light on the dash not to work? I had two trucks and neither worked and my friend had his pre heater stop working.

Any help will be appreciated, gary

gary@halftracks.com

 

[Westech]

Really G102.. I have a M813A1 and you really think that little glow plug is worth a ****? Even when working its like peeing on a forest fire.
So anyway The light should be on, check the bulb step #1. test if there is power to the GLOW plug step #2 take out the GLOW plug and test it. step #3. If still not found problem it may be the switch. Just start at #1 and work your way around. I'm sure you will find the problem why its not working. But stated above might be a deal breaker lol

 

[jasonjc]

The pre heat is 12Volt, It has one wire that hooks to one bat make shure that it is hooked up and is hooked to 12 volt only.

 

[70deuce]

If the circuit is wired correctly and intact, 12V, the light should come on whether or not the glowplug is working correctly. My M818's glowplug had a broken element. the light on the dash still came on. Also found that when I picked the truck up from GL, the cold start circuit was wired to 24 volts which is incorrect. As stated it should be 12 volts and the wiring diagram decal on the underside of the battery cover, the one that serves as the right side cab step, shows which battery it should be hooked too and without looking I think its the rear left battery as you look at them.

 

[70deuce]

I was right the power for the 12 volts comes off the rear left battery's positive terminal. The circuit number is 569 and is hard to follow in the diagram but check my finger pointing to the terminal and the single wire coming off it is the power source for the glowplug. Tha may be another decal for Gary to tackle.

 

[g102]

Thanks Deuce for the pictures, I will take off the battery cover today and check it out. I had two of them from TN. and neither of them worked. who knows they may have been disconnected. If it was installed on the vehicle I would like to have it working even if it's not a huge help in starting but with the cold we have had in IL everything helps, Thanks for the help, Gary

 

[jwaller]

With the weather being in the low 30's here in sc my 818 will not start without the clod start assist. I'm glad mine works. saves a lot of cranking on the starter.

 

[vinny-socom1]

Nice I did not know it needed to be 12v I think mine is wired for 24v I guess thats why mine doesn't work. Thanks Vinny

 

[cranetruck]

Here is a link to a PS magazine note on this subject:
http://old.steelsoldiers.com/index...._starting&name=gallery&include=view_photo.php

 

[g102]

I checked out the battery box and sure enough the wire was connected to the 24V battery. I changed it to the 12V. side and the light works and I could feel the manifold getting warm. I didn't try spraying and fuel at this time. Weird part is I took a test light and it didn't show any power or light up. Thanks to everybody for the help and the decal location. I never noticed it before. Gary

 

[70deuce]

Gary, better yet is a block heater. That really helps these big motors fire up quick.

Phil

 

[CMSGT]

Question: I know the plug fot the heater is 12VDC, what is the actual voltage that you can read on the top of the plug when its operating? I only get 10 VDC. At first I was only getting 4VDC until I went through the circuit and cleaned all the connections, also my dash light was barely lit and the battery that the plug was connected to would drain pretty fast compared to the others when cranking (they are all only a few months old). After I cleaned all the connections the light was bright and everything appeared to work correctly, but the battery drain and the 10 VDC instead of 12 concerns me as something else may be grounded in that circuit. Any info is appreciated.

 

[jwaller]

dunno, but if you are getting 10 and the other end of the same lead is 12 then it's going somewhere. what are you seeing from the back of the switch. I'd just look at every place from the battery to the plug and see where it's disappearing.

 

[CMSGT]

I cant find a wiring diagram with each lead on it but at the switch I have 12 until I turn it on then its all 10 so I just wasnt sure if the plug would drop it 2vdc or not.

 

[jwaller]

I imagine it could. you are turning on a serious resistor to create that amount of heat.

 

[area52]

I thought I read in one of the TM's that the resistor was 6V? so it drops it from 12V to 6V.