Glow Timer Blows 5A Fuse

[Gregster613]

I wanted to ask if anyone else has had issues with their glow timer malfunctioning (out of the blue)? I just replaced my combo switch, put it all back together, went to start it up and no go! I had no timer light, checked the fuse and it was blown. Put in fresh fuse and it blew instantly. I tore it back apart, unplugged my timer put another fuse into the slot. It held good while the timer was out of the system but blew as soon as I plugged the harness into the timer.

I "ASSUME" that means the timer went bad? I ordered a new timer and I'll know for sure once it gets here but I wondered if anyone else has had something like this happen to them? I'm not the sharpest with electrical issues and have not a clue how to trouble check the old timer? I do know that I get a constant 12V to one side of the fuse spot in the fuse block - all the time, even with switch off. I don't know if that's supposed to be so or not. I've never had issues with the glow system before. I've read about a lot of glow plug issues and am ready for that side of the troubles -- but the timer malfunctioning? Not so much!
If anyone has advice, I'm all ears!! Thanks Greg

 

[oldnslo]

Does the other side of the fuse connection show continuity to ground with the timer plugged in but fuse removed? If yes then something in the timer circuit has failed - shorted to ground which would cause the fuse to blow.

 

[garry1p]

replaced my combo switch, put it all back together,

If the glow timer was working OK before you replaced the combo switch I would suspect something other than the glow timer.
What is connected to the combo switch that could cause the problem?

 

[Gregster613]

Does the other side of the fuse connection show continuity to ground with the timer plugged in but fuse removed? If yes then something in the timer circuit has failed - shorted to ground which would cause the fuse to blow.

Oldnslo, Good question - I don't know, I'll do that type test tomorrow. Thanks for the thought/advice and I sure hope nothing in the circuit just went bad. I hate trying to trace out lines, etc., etc.

 

[Gregster613]

If the glow timer was working OK before you replaced the combo switch I would suspect something other than the glow timer.
What is connected to the combo switch that could cause the problem?

I know it worked the last time I started up the tractor. A lot of things are combined in the combo switch - horn, high & low lights, turn signals. Nothing with the glow system though. They all are working great with the new switch in place. Which is what stumped me. I put the dash all back together; tested the new switch to ensure all was working and thought great! Today I went to run the rig and found out the no go. I've ordered a new timer and when it arrives I'll find out if that was the issue or not. I just thought I'd ask if this had occurred to anyone else before. I do suspect it was just coincidence that it happened. Least that's what I hope!

 

[Jake99]

I "put the dash togheter", than i would look there first.i dont know your dash.
Timers can fail for sure, but my guess is wire that got pinched or something thats is touching a ground. That timer has a output to the glowplugs. Bypass the timer with a piece of wire.
If u can send us a photo of your timer we can assit in how to troubleshoot this further.

 

[Gregster613]

Does the other side of the fuse connection show continuity to ground with the timer plugged in but fuse removed? If yes then something in the timer circuit has failed - shorted to ground which would cause the fuse to blow.

Oldnslo, I got sidetracked moving some brick blocks for the wife, but I got to do the test you suggested and.......

no - (zero for continuity) but (yes to resistance). Meter showed .013 -- .016 from the other side of fuse to ground. The other side of fuse spot shows battery voltage which is high 12v. This test was done with the entire dash disassembled, everything unplugged, wires just hanging loosely, lower dash also entirely off, thus ignition switch unplugged and out of circuit. The only item/wire I reattached for the test was the glow timer relay plug. So I'm wondering whether that means the glow timer relay is bad?

I am aware that 273/293's were known to have shorted wires in the harness where it passes between chassis and frame but mine has no visible shorts! I also have NO wires pinched underneath or inside of the dash. All is as it is supposed to be except that my glow light/system does not seem to function.

The timer I'm looking at/holding in my hands looks just fine from the outside view of it. No melted spots, no visible looks of distress, it just appears to not be working and I don't know how to test it with my voltmeter. IE...I don't know it it should show continuity between any of the prongs or resistance or if anything at all. My manual doesn't show any means of troubleshooting this item. It shows how to troubleshoot several other switches, etc., etc. but not this one.

But, the manual also talks of a glow relay which I am unable to find anywhere in the system. I just find the glow timer.

It's probably the timer that is bad and when my replacement gets here I'll then know for sure. I was just trying to find out if anyone had troubleshot/tested their timers and how to do so. Vise just replacing to find out. Greg

 

[oldnslo]

.013-.016 ohms is basically a dead short to ground

Formula is E(volts) = I (amps)x R( ohms) or transposed volts/ohms = amps. 12 / .014 = 850 amps so Houston we have a problem..

 

[Gregster613]

.013-.016 ohms is basically a dead short to ground

Formula is E(volts) = I (amps)x R( ohms) or transposed volts/ohms = amps. 12 / .014 = 850 amps so Houston we have a problem..

Okay then, but, where would that short possibly be? Inside the timer is my hope, because the wires all appear to be intact and ok. If internal to the timer there shouldn't be /might not be any visible clues? That's my hope for now at least!

 

[Gregster613]

Okay then, but, where would that short possibly be? Inside the timer is my hope, because the wires all appear to be intact and ok. If internal to the timer there shouldn't be /might not be any visible clues? That's my hope for now at least!

I had edited to add but it appeared not to save so here again. I don't know much about voltmeter usage but I thought that when the ends were touched together set on ohms (upside down U) and it gave 0.0 reading that was = to a dead short? That's what I get when I do that. It shows a direct connection to each prob and = an open line?

If I get some other reading as I did, wouldn't that mean resistance of some sort? I told you oldnslo I don't fully understand the meter or what I'm supposed to be seeing?

I was attempting to determine if there was an internal short in the timer but don't really know how to to that. I've got a timer (a small black box with 6 male probes) and wanted a way to determine it was functional by testing probes for shorts between them but am way off in my thinking I guess. My manual shows no way to test the timer, so I guess replacement is the only way to test? Thanks for any more and all help given! Greg