Relays

[Jesse masterson]

Can some one tell me what the middle relay on a 2008 dk45s goes to, there are 3 on the firewall . Left is starter,right is glow plugs. Middle??? From sitting on tractor looking forward.

 

[Kioti Paul]

I also have a DK45, with the same 3 relays. On mine, the left one is also the start relay, the middle one , according to my wiring diagram is the glow plugs (it has a large Black / Yellow striped wire in the front- Black/Red in rear), the Right one (White wire in front, Blue wire in rear),, I can't find anywhere in the schematic.

If I unplug the right relay, the engine won't start (it will crank normally, just will not run). If I unplug the middle relay, the engine cranks and runs normally; & I can't find anything that isn't working. Being in Nth Texas, the engine might well start normally without the glow plugs (it is 60 deg right now).

I have heard on this forum that the third relay is to operate the injector run solenoid. I can't find any mention of an injector run solenoid (or relay) anywhere in my shop manual.

I have found my manual to be so poorly written, lacking any detail, and just out right WRONG so many times in the past, I really have no confidence in it; however, I do feel that whatever relay you have that has Black/Yellow, and Black/Red wires in the front & rear, is the glow plug relay, the relay with Red, and Red/Blue wires is the starter, and finally the one with White, and Blue wires (probably) has something to do with fuel delivery - but I'm not sure exactly what or how.

I am confidant someone with specific experience with this relay will explain.

 

[MichiganIron]

Fuel Shutoff Solenoid. That's why the tractor will crank but not start, the fuel shut-off solenoid is still closed when the "right" relay is unplugged.

Hope this helps

 

[Jesse masterson]

So the middle is the fuel shutoff solenoid?or the right one. When I unplug the right one my glow plug light on the dash will not come on. So I assumed the right one was glow plugs. Problem has been it’s in the 40s here and if I put glow plugs on timer with waiting till light goes off exhaust will smoke while cranking but won’t start, if I turn key past timer to manual glow plugs it starts right up. Could be the larger black box which is the glow plug timer box which is probably expensive to try first so I thought start with cheap relays

 

[Kioti Paul]

It is starting to sound like our tractors are not as similar as I thought. Mine is a 2008(serial # GC4900201) DK45sc, but I do not have a manual position for the glow plugs. Also, with either (or both) of the relays unplugged, when I turn the Ign switch on, the glow plug light still comes on normally, which makes sense to me because the glow plug timer box is what turns both the relay and the light on. I would check the fuse for the timer box; if it is good, it would seem to me the timer box is the most likely culprit since the "manual" glow plug position works. I'm sure that position feeds the relay, so the relay must be good.

Look at the front wire at each of the relays, if one of them is Black and Yellow - that is the glow plug relay, if one of them is White, that is the stop solenoid relay, the start relay should have a Red wire in front. If these wire colors are not the same on your relays, I guess we have very different wiring.

If you have a manual position, why not just use that? (as opposed to spending big cash for the timer)

Good Luck

 

[Jesse masterson]

I very may well just do that but I kinda like fixing things as they go wrong, just me! Lol mine is a dk45s not a se so they may be different. Thanks more the help it is appreciated

 

[Jesse masterson]

Also if you turn your key just past timer on glow plugs but not quite far enough to hit starter glow plugs engage manually I just stumbled on this there is no marking on switch to inform someone of this u may have it also, u can use it for extra heating if it’s real cold after timer goes off to aid in cold start. I’ll bet yours might be the same.

 

[Kioti Paul]

I do have the manual heat position on my switch, I've owned the tractor since new & never knew it existed. My switch placard does have a "Heat" position, but there is no detent, and the light does not come on. The only way I can tell it is working is that if you listen closely, you can hear the relay 'click', and you can see the voltmeter 'dip'. Can't find any mention of it in the owner's manual. The service manual does show this position, and gives a pretty good description of the "Glow Plug System". Good to know!

There are 6 wires going to the "PreHeat Controller", and they should be quite easy for you to check using a voltmeter, or a test light. First, unplug the controller, and unplug the starter relay, then check that the wires are connected as follows:

If I can figure out how to do it, I will attach a file showing the plug diagram and wire labels from my manual.

#1 wire Red/White should have battery voltage with ign switch on
#2 wire White/Green goes to the water temperature switch; should be grounded. (open when water temp is above 60C) * check this one closely; if your problem is a bad temp sensor, should be a cheap fix.
#3 wire Blue/Black should have battery voltage with ign switch to the start position (reason for unplugging start relay)
#4 wire Black/Red goes to Glow Plug Relay coil. Using same procedures as for #8 wire, you should hear the Glow Plug Relay 'click'.
#5 wire Black goes to ground
#6 wire - not used
#7 wire - not used
#8 wire Green/Red goes to dash light (I believe you've already proven this one is correct) To check, 1st use an ohm meter, and test for
around 100 ohms to ground, if at least 50 ohms, then using a small, thin wire as a jumper, touch this wire to the
Red/White wire gingerly (ign switch ON), watching for any sparks!! If no sparks, then see if the dash light is on.

I do agree with you on keeping the tractor with all functions working!

 

[Jesse masterson]

I do have the manual heat position on my switch, I've owned the tractor since new & never knew it existed. My switch placard does have a "Heat" position, but there is no detent, and the light does not come on. The only way I can tell it is working is that if you listen closely, you can hear the relay 'click', and you can see the voltmeter 'dip'. Can't find any mention of it in the owner's manual. The service manual does show this position, and gives a pretty good description of the "Glow Plug System". Good to know!

There are 6 wires going to the "PreHeat Controller", and they should be quite easy for you to check using a voltmeter, or a test light. First, unplug the controller, and unplug the starter relay, then check that the wires are connected as follows:

If I can figure out how to do it, I will attach a file showing the plug diagram and wire labels from my manual.

#1 wire Red/White should have battery voltage with ign switch on
#2 wire White/Green goes to the water temperature switch; should be grounded. (open when water temp is above 60C) * check this one closely; if your problem is a bad temp sensor, should be a cheap fix.
#3 wire Blue/Black should have battery voltage with ign switch to the start position (reason for unplugging start relay)
#4 wire Black/Red goes to Glow Plug Relay coil. Using same procedures as for #8 wire, you should hear the Glow Plug Relay 'click'.
#5 wire Black goes to ground
#6 wire - not used
#7 wire - not used
#8 wire Green/Red goes to dash light (I believe you've already proven this one is correct) To check, 1st use an ohm meter, and test for
around 100 ohms to ground, if at least 50 ohms, then using a small, thin wire as a jumper, touch this wire to the
Red/White wire gingerly (ign switch ON), watching for any sparks!! If no sparks, then see if the dash light is on.

I do agree with you on keeping the tractor with all functions working!

Thanks for the info I will put it to use as soon as it warms up some. Thanks again for the help.

 

[grsthegreat]

I never realized this with my 2010 era DK45, if i hold key just to a point before it turns over, the glow plugs engage, and after 4 -5 seconds the glow plug light came on. I could hear to relay kick in and the dash lights dimmed so i know glow plugs engaged. That was good to know. Thank you previous poster, as i did not know i had this function. I can use it on cold days after shes sat for 30 minutes. Usually it not cold enough to trigger the auto glow plug cycle, but she starts hard.