Cold start wiring diagram

[kurtkds]

Any body have the wiring diagram for the cold start circuit for an M818? I've looked through the TM's that I have but have had no luck. I'm not quite ready to reverse engineer it yet.

I'm trying to figure the operation of it, specifically if there is a timer involved similar to the "wait to start" in a CUCV or if it comes on when you flip the switch.

 

[cranetruck]

Isn't it covered here?

 

[kurtkds]

That looks to be what I'm looking for! Is that in a 5 ton specific TM?


I thought that you would chime in at some point with a solution.

Which TM did that come out of, I'd like to be able to print out a full size copy.

I was curious about the operation of that circuit because of the comment in the -10 about wait 30 seconds and if light does not come on call for help.

 

[jwaller]

no timer. 1 12V wire from pos terminal of 1 battery to the switch on dash. then a wire going to the light on dash and the plug on the intake manifold.

read the data plate on the dash for proper operation of the cold start system. light should come on as soon as you turn the switch. it's direct wired to the battery.

IT IS 12VOLTS!!! check the light if it's not coming on.

if it's dim, replace it with a 12V light. the TM's show it as a 24V bulb but it's a 12V circuit.

 

[cranetruck]

Kurt, it's the 260-20 TM July 1972...

 

[kurtkds]

Ok, I found this in the elec. trouble shooting section under the heading of "heating system".. I guess I was not using a broad enough search pattern.. lol

Cranetruck the 260-20 that I have has the most current date of Apr 1995.

 

[kurtkds]

read the data plate on the dash for proper operation of the cold start system. light should come on as soon as you turn the switch. it's direct wired to the battery.

The dash instructions were what I'm following, the -10 had the statement about the light not coming on in 30 seconds, that is where I was hung up.

It hasn't been cold enough here since I picked up this truck to test out the cold start circuit, but I had planned on getting into the wiring with a meter to check things out to make sure that it was ok before I REALLY needed it.

The light does come on as soon as the switch is turned on, I figured that if anything I would check the glow plug, that seems to be the part that would fail first.

 

[papercu]

One of the nice things about the electronic version is the ability for searching. The 1995 version has
"COLD START SWITCH - Controls 12-volt power to activate or deactivate cold starting system.
COLD START RELAY – Maintains glow plug voltage by reducing the resistance in series with
glow plug during cranking.
COLD START RESISTOR – Regulates 6-volt power to cold start indicator and glow plug".
There is a relay and a Resistor Assembly after the switch. Wayne

 

[jwaller]

Ok, I found this in the elec. trouble shooting section under the heading of "heating system".. I guess I was not using a broad enough search pattern.. lol

Cranetruck the 260-20 that I have has the most current date of Apr 1995.

that last diagram is in error. the cold start switch in only a 2 position switch. it's either off or on, there is no start position.

 

[kurtkds]

that last diagram is in error. the cold start switch in only a 2 position switch. it's either off or on, there is no start position.

I had caught that too. I wonder if they had tried to run it that way and figured that it didn't work too well and went back to a traditional switch..

 

[70deuce]

Definitely make sure it wired at the batteries for 12 volts. My M818 had the system powered by 24 volts and the glow plug was fried. Two large resistors on the firewall bring the voltage down to 6 volts for the glow plug and man do they get hot even with 12 volt power.