Glow Plug Timer control units

dippa · Sep 3, 2015

Thanks for your replies. Forgot to mention earlier that I already tried to replace diode D3, but it didn't change anything. I also measured that blue resistor today and that was also ok (despite that looked a little bit overheated).

Here is glow relay wiring schematic from workshop manual:

If I'm reading that correctly, wiring looks same than SG51Buss's pictures, so that S85-NC should work also ok on my excavator? Or does that extra pin on timer really needs some signal from temperature sensor? Glowing time is of course different in S85-NC timer than my previous, but I think that is not a issue in real life...

skyhook · Sep 4, 2015

I would think it would need a signal on pin 5,
theres not that much on that board, bring it in to a tv repair shop etc, or if you can, replace the transistors and capacitors, check all diodes, looks like theres a few zener diodes, check those also.

The Fred · Sep 4, 2015

Mouser.com has every component very cheap to purchase for those repairs.

Fred

JRobyn · Sep 8, 2015

With no connection at all to the engine temp lug, the timer would either give you max on time or min (I don't know which), but should work either way.

- Jay

Don H · Nov 5, 2015

Glad I found this thread!

I have a 1988 Ford 1520 that has working glow plugs but the dash indicator light does not light when I key over to activate the glow plugs. I believe the problem is the timer but the cost from the dealer is $120!

I tested the timer as shown above. The test showed no power indicating the timer was bad. Figuring I had nothing to loose (except $120) I took the timer apart and cleaned it with contact cleaner, reassembled and now the light works!

I checked power to the glow plug while keyed over to the glow plug position, with the ignition in the ON position and in the START position. The glow plugs only work when the ignition is keyed to the GLOW PLUG position as they should.

I've read that others have tried the cleaning trick but it was only temporary. We shall see.

PILOON · Nov 5, 2015

My solution:
KISS
Heavy duty momentary switch capable of the amperage
or a relay + momentary push switch.

Push switch and count: thousand and one, thou and 2, etc for about 10 seconds and attempt a start, if no start count again maybe 15 secs.
She starts every time!

Cabanon · Feb 23, 2021

Hello, I know this thread is close to 6 years old now but this is the only place I found useful info regarding the glow plug timer relay. My dad has a Nissan N150 mini excavator with a S81NJ timer relay that I suspect is bad. I opened it up and all 4 caps inside were loose and desoldered. I thought this was very bad so I resoldered them all and tested it with the OP's method, but the light does not lit up at all. What I find very odd is the D6 diode make it impossible to have any current in position 6 as the cathode block any form of voltage/current to go through this pin. or am I mistaken ? I did tested all diode and all seems to be good.

I don't know where SG51Buss found these cool NGK diagram but I would very like to get one, if possible, for this model.

here's some pictures of the unit itself. maybe I'm missing something to check ?

aczlan · Feb 23, 2021

It looks like there's a Mitsubishi part MM431762 which crosses to that NGK part number which is available for $25 on eBay.
I might go that route if the components on the board all seem to test properly.

Aaron Z

Cabanon · Feb 24, 2021

yes this is also the other possibility. was looking to repair it as we order daily from mouser / digikey so getting the part and fixing it is not an issue. only downside from ordering on ebay is the lead time, but he's not using the excavator has it's winter time here.

BravoXray · Feb 24, 2021

Did you test the caps? If they are more than a few years old, they can dry out and go way out of tolerance.

Texasmark · Feb 26, 2021

On the 6 year old topic....glow plugs, I read a few days ago that glow plugs in general have a limited life so timing is important...don't run longer than necessary. With that said, older plugs took about 30 seconds to operate adequately for cold temps, not the coldest but cold temps. Currently designed plugs operate in single digit seconds. I just bought a 2020 tractor, thinking the GP timer had malfunctioned as compared to my other tractors with the newest being 2016 since with them, the heater and indicator would stay on the longer period. The new one turned off just a few seconds after illumination as did the plug...you could hear the relay clicking on a cold day. Well on a colder day I tested it and they stayed on for a longer period but still less than 10 seconds. So I quit worrying about that.

RalphVa · Feb 26, 2021

SG51Buss said:
The glow plug indicator lamp on my New Holland TC35 Boomer would occasionally come on, and now it just stays on.
According to the helpful threads in this forum, the cause is a faulty glow plug timer unit:

Glow Plug Problem

Pulled the unit, bench tested it per this procedure, and sure 'nuff, it's bad.
View attachment 410473 View attachment 410474

One never worked or never had it installed on the JD 4010. I just paused between "on" and "start" to a count in my head: 1 or 2 seconds in warm weather and about 6 seconds in cold weather. Always started with the usual 1/2 turn I'm used to from 39 years of running car diesels and 16 years of tractor diesels. Something not right if they don't start in that 1/2 turn of the crankshaft. Even the old 220D did this at -22 F (after a LONG glow period for it).

Ralph

PILOON · Feb 27, 2021

Best practical timer!*
Thousand and one, thou + 2, etc. etc. (up to about 7/8)
And if no start, repeat and add a few thou's,
A push button switch preferred but even pinching the wires can suffice when in a pinch.

* however with current trends many would like to accomplish their start by using their cell phones.

RalphVa · Feb 27, 2021

Glow plugs on the 240D lasted to near 200k miles. That's probably about 6000ish tractor hours.

Cabanon · Apr 7, 2021

BravoXray said:
Did you test the caps? If they are more than a few years old, they can dry out and go way out of tolerance.

Hi, no I did not as I'm not sure how to do that. Anyway my father went the straight route with a push button only and it's working.

miha · Apr 22, 2022

Cabanon said:
Hello, I know this thread is close to 6 years old now but this is the only place I found useful info regarding the glow plug timer relay. My dad has a Nissan N150 mini excavator with a S81NJ timer relay that I suspect is bad. I opened it up and all 4 caps inside were loose and desoldered. I thought this was very bad so I resoldered them all and tested it with the OP's method, but the light does not lit up at all. What I find very odd is the D6 diode make it impossible to have any current in position 6 as the cathode block any form of voltage/current to go through this pin. or am I mistaken ? I did tested all diode and all seems to be good.

I don't know where SG51Buss found these cool NGK diagram but I would very like to get one, if possible, for this model.

here's some pictures of the unit itself. maybe I'm missing something to check ?
View attachment 687593 View attachment 687594 View attachment 687595

Hello, maybe you know the value for resistor R6 and R7? Thanks

tagnamee · Apr 28, 2022

In researching a possible replacement for my TC40 Glow Plug Timer, (NGK and some other knock offs) I came across a Hella adjustable 10A relay. It can be adjusted from 0 - 900 seconds of on or off time. Any comments?

dlctcg · Apr 28, 2022

Just not sure what advantage you would get by using the Hella adjustable relay? Or how much it will save $$ wise?

You would have to cut the factor harness & wire it correctly... which is probably easy enough but being you can buy a direct plug in aftermarket replacement for around $20+...
I don't think I would be cutting my factory harness...

I would double check but I believe this will work on you NH TC40DA: Glow Plug Timer SBA385870301 for New Holland TC35 TC35D TC40 TC40D TC45 TC45D

tagnamee · Oct 25, 2022

I know this thread is quite old but I am trying to address a failed GP timer issue. Yes, purchased the Jeeda part off Amazon and it crapped out after 2 months. Instead of all this monkeying around, what are any thoughts about installing a momentary switch on the ground circuit and counting to 5. According to Messicks, this is a $120 fix and I still have no confidence it will last. This is for a TC40DA Vintage 2004. I would appreciate any comments or suggestions to resolve on a long term basis.