No lights on my TC45DA
- Thread starter fishpick
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fishpick
Platinum Member
Wrenchguy - well, I was back at it and am even more confused...
So off the rotary switch there are 3 contact and 2 of the 3 have 2 wires, one of those wires (in the 2 wire cases) goes to the dashboard. On setting one on the switch it's supposed to illuminate the dash, switch setting 2 has a single wire and that is low beam and the switch setting 3 has 2 wires, one for the high beam light indicator on the dash and the other to the lights.
Get this - when I pull the plug out of the back of the dash console and test these wires - they are sending 12V to the dash... But there is no backlighting or respective high beam... So from the dash unit I pulled the bulbs that do those things and tested... They are fine. Time for a WTF?!?
So, after that I decided to pull both connections to the rear of the tractor to make sure the part of the circuit that lights the red rear lights wasn't causing an issue... And still nothing. When I test across the switch and it makes contact I get my 11.8V... But testing from the switch to the end of a wire that goes under the hood I get nothing. There's only about 2' at most of wire between those two points and I see nothing wrong.
Also - this whole relay rat hole I sent myself down was a waste... Looking at the schematic (which I'm starting to question) the relay ONLY comes into play for the work lights... The primary lights with the rotary switch have nothing to do with that relay at all. It's fuse, switch, wire, bulb.
I hate this - now I'm gonna have to pay some dude to fix a wiring issue because I have dumped a pair of days into it and don't own / have access to the $500 real manuals to fix things... Not happy.
So off the rotary switch there are 3 contact and 2 of the 3 have 2 wires, one of those wires (in the 2 wire cases) goes to the dashboard. On setting one on the switch it's supposed to illuminate the dash, switch setting 2 has a single wire and that is low beam and the switch setting 3 has 2 wires, one for the high beam light indicator on the dash and the other to the lights.
Get this - when I pull the plug out of the back of the dash console and test these wires - they are sending 12V to the dash... But there is no backlighting or respective high beam... So from the dash unit I pulled the bulbs that do those things and tested... They are fine. Time for a WTF?!?
So, after that I decided to pull both connections to the rear of the tractor to make sure the part of the circuit that lights the red rear lights wasn't causing an issue... And still nothing. When I test across the switch and it makes contact I get my 11.8V... But testing from the switch to the end of a wire that goes under the hood I get nothing. There's only about 2' at most of wire between those two points and I see nothing wrong.
Also - this whole relay rat hole I sent myself down was a waste... Looking at the schematic (which I'm starting to question) the relay ONLY comes into play for the work lights... The primary lights with the rotary switch have nothing to do with that relay at all. It's fuse, switch, wire, bulb.
I hate this - now I'm gonna have to pay some dude to fix a wiring issue because I have dumped a pair of days into it and don't own / have access to the $500 real manuals to fix things... Not happy.
Bob Boyington
New member
- Joined
- Dec 17, 2011
- Messages
- 1
- Tractor
- New Holland TC40D
I just had my TC40D lights worked on at the dealer. No headlights (sparadic) and turn lights were messed up. Dealer replaced headlight switch on the dash but had to also replace the flasher sensor. Cost of the sensor was $173. A New Holland part so probabally no after market. If not the fuse maybe the dash switch could be the culprit. My part # was 86558431 cost $31.46. Hope that helps.
jinman
Rest in Peace
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- Feb 23, 2001
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- Texas - Wise County - Sunset
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- NHTC45D, NH LB75B, Ford Jubilee
Fishpick, the next time you are out in the barn in the freezing weather, is it possible to take a cell phone photo or regular photo of your relays and post it? A photo would help us be sure we are on the same page and talking about the same relays. Your headlight relay is a heavy duty relay. It's likely different from the hazard lights, blinkers, or rear worklight relays.
OP
fishpick
Platinum Member
@Bob - I have tested out the switch and even jumped it and that doesn't seem to be it. As for the turn signals - they work fine, so the expensive part is safe for now 
Jinman - Ok, here's the schematic from the manual AND the photo I just snapped. On the schematic I circled the most simple test case on the switch - setting 1 - light the dash and the rear lights... Follow the red line and you will see it never it's the relay... But still want light the rears. Now, actually if you follow ANY of the lines from the rotary switch - NONE pass anywhere near the relay. The relay appears to be reserved for the use of the work lights only. And the work lights work.
Now, for the photo of the relay panel... When I pull the circled one, the work lights die... So that's the light relay... But see above and the schematic pic.
Finally, if these are rotated or upside down... Blame the iPad and the TractorByNet iPad app... No way to orient the pictures... Sorry guys. But thanks for the help, I need it, I'm fresh out of ideas!
Jinman - Ok, here's the schematic from the manual AND the photo I just snapped. On the schematic I circled the most simple test case on the switch - setting 1 - light the dash and the rear lights... Follow the red line and you will see it never it's the relay... But still want light the rears. Now, actually if you follow ANY of the lines from the rotary switch - NONE pass anywhere near the relay. The relay appears to be reserved for the use of the work lights only. And the work lights work.
Now, for the photo of the relay panel... When I pull the circled one, the work lights die... So that's the light relay... But see above and the schematic pic.
Finally, if these are rotated or upside down... Blame the iPad and the TractorByNet iPad app... No way to orient the pictures... Sorry guys. But thanks for the help, I need it, I'm fresh out of ideas!
OP
fishpick
Platinum Member
After that last post I thought I'd make crystal clear what's what...
The red circles are parts of the circuit that have voltage as expected... So all 3 positions on the rotary and the front work lamps at the lamp and at the 4prong plus under the hood.
Now, the blow circles are where the test for low/high beam fail on the front lights at the 4prong plug... But according to the schematic that wiring harness between the switch and the plug has nothing in it and although I haven't cut it open its in great shape and the wires should be fine.
The red circles with the blue lines, well, that's the wires from the switch to the dash panel... They test out with 12v at the plug into the panel... But the dash never illuminates at setting one and the high beam indicator light never comes on on setting 3...
There's about 50 other marks I cold put on here when I have tested... The point is there's 12v at the switch, not 12v on the other end of the wire that comes from the switch and the massive wrapped harness is all that between those two points. The relay has nothing to do with things...
I hate electrical messes. Gimme a gasket anyway over this mess!
The red circles are parts of the circuit that have voltage as expected... So all 3 positions on the rotary and the front work lamps at the lamp and at the 4prong plus under the hood.
Now, the blow circles are where the test for low/high beam fail on the front lights at the 4prong plug... But according to the schematic that wiring harness between the switch and the plug has nothing in it and although I haven't cut it open its in great shape and the wires should be fine.
The red circles with the blue lines, well, that's the wires from the switch to the dash panel... They test out with 12v at the plug into the panel... But the dash never illuminates at setting one and the high beam indicator light never comes on on setting 3...
There's about 50 other marks I cold put on here when I have tested... The point is there's 12v at the switch, not 12v on the other end of the wire that comes from the switch and the massive wrapped harness is all that between those two points. The relay has nothing to do with things...
I hate electrical messes. Gimme a gasket anyway over this mess!
WM75Guy
Elite Member
Is your tractor geared or HST? My HST has high and low beams, it appears the geared does not. Have you checked continuity on HM55 from the switch to the headlight plug? There is a connector in between the switch and the headlights that the work lights use also. If the worklights come on it probably is not the culprit. The ground goes thru it also.
Do the tailights work with the switch on? They do not go thru the connectors to the headlights once they leave the switch plug (wire HM53), neither do the dashlights (wire HM54). They both come out the same place on the switch. If they are not working it could be the switch.
It's possible the switch or wire is allowing voltage but not amps thru it. I have seen this occassionally on fire trucks. Will light a test probe but not a light bulb. On a stranded wire if only 1 strand is still intact it will pass voltage but not enough amps to do anything. Same with the switch, only enough contact for voltage.
Do the tailights work with the switch on? They do not go thru the connectors to the headlights once they leave the switch plug (wire HM53), neither do the dashlights (wire HM54). They both come out the same place on the switch. If they are not working it could be the switch.
It's possible the switch or wire is allowing voltage but not amps thru it. I have seen this occassionally on fire trucks. Will light a test probe but not a light bulb. On a stranded wire if only 1 strand is still intact it will pass voltage but not enough amps to do anything. Same with the switch, only enough contact for voltage.
jinman
Rest in Peace
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- NHTC45D, NH LB75B, Ford Jubilee
Bob, you are right. Your tractor is a different "beast" from mine. The key to this problem is the area of the connector where you have the blue circle. I'm gonna talk about the normal beam here because we need to work on a single circuit at a time.
As you said, the relay on your tractor controls only the work lamps that are controlled by the work lights switch and the relay. Your headlights show to be powered directly off the switch. The switch connector pin #3 is headlight power and is a dark blue wire (I'm not sure of pin #3 because it is blurry). That exits the light switch and goes to pin#1 of the connector you circled in blue. From there, it goes to splice #15 (SPL-15).
Now, the wacky part of this is that all the wires leaving the switch are dark blue. You want to follow the line marked "HH-52". I would normally say to check your ground circuit, but the work lights use the same ground path through splice #17. If they are working, ground must be good. Pin A of the light connector should be ground and pin B should be the +12 vdc. If I had power coming out of the switch, I would be tempted to run a jumper up to see if the lights work by bypassing the harness completely. I can't tell for sure what pin on the switch HH-52 is attached to because the diagram is blurry when I zoom in to read the number, but I think it is pin #3.
As you said, the relay on your tractor controls only the work lamps that are controlled by the work lights switch and the relay. Your headlights show to be powered directly off the switch. The switch connector pin #3 is headlight power and is a dark blue wire (I'm not sure of pin #3 because it is blurry). That exits the light switch and goes to pin#1 of the connector you circled in blue. From there, it goes to splice #15 (SPL-15).
Now, the wacky part of this is that all the wires leaving the switch are dark blue. You want to follow the line marked "HH-52". I would normally say to check your ground circuit, but the work lights use the same ground path through splice #17. If they are working, ground must be good. Pin A of the light connector should be ground and pin B should be the +12 vdc. If I had power coming out of the switch, I would be tempted to run a jumper up to see if the lights work by bypassing the harness completely. I can't tell for sure what pin on the switch HH-52 is attached to because the diagram is blurry when I zoom in to read the number, but I think it is pin #3.
OP
fishpick
Platinum Member
@repowel - alright, I have to admit when I read your post last night I thought you were full of it... "a wire that carries full voltage but no amps" that's just silly talk... So, well, um... You are a genius!
This am I started at it again... And I figured I'd do exactly what jinmans last post suggested (even before I saw it)... And I started at the fuse. Well, hang on, what's this right under the fuse, on about 1/2" pigtail... Ahhh, yes, the joys of owning a very slightly used tractor. A SPLICE! Never would have seen it except I had pulled the side of the fuse clip that's not on the bus bar down and out to trace the wire... A friggin splice! Suddenly, I thought of repowel's post and blushed a little... Could it be?
Tested the voltage and it was fine, flipped to amps on the meter... Nary a flicker. Another round of WTF expletives in the barn... But hope. So, grabbed the small alligator clip testing wire rig thing, went over the splice directly to the switch (30) and the glory of angles shown upon me... Well, really just headlights, but it it is Christmas...
I'll be damned...
There is such a thing a a wire that passes voltage but no amps...
Thanks all... Again through the miracles of the interwebs, community farming is still possible in 2011.
I love you guys... In a completely manly tractor talk sort of way!
This am I started at it again... And I figured I'd do exactly what jinmans last post suggested (even before I saw it)... And I started at the fuse. Well, hang on, what's this right under the fuse, on about 1/2" pigtail... Ahhh, yes, the joys of owning a very slightly used tractor. A SPLICE! Never would have seen it except I had pulled the side of the fuse clip that's not on the bus bar down and out to trace the wire... A friggin splice! Suddenly, I thought of repowel's post and blushed a little... Could it be?
Tested the voltage and it was fine, flipped to amps on the meter... Nary a flicker. Another round of WTF expletives in the barn... But hope. So, grabbed the small alligator clip testing wire rig thing, went over the splice directly to the switch (30) and the glory of angles shown upon me... Well, really just headlights, but it it is Christmas...
I'll be damned...
There is such a thing a a wire that passes voltage but no amps...
Thanks all... Again through the miracles of the interwebs, community farming is still possible in 2011.
I love you guys... In a completely manly tractor talk sort of way!
jinman
Rest in Peace
- Joined
- Feb 23, 2001
- Messages
- 21,008
- Location
- Texas - Wise County - Sunset
- Tractor
- NHTC45D, NH LB75B, Ford Jubilee
What you are describing is called contact resistance due to a poor connection. You can measure voltage, but as soon as a load is applied, there is little or no current. In most instances, if you measure the voltage while trying to to apply a load, you will see it drop to zero also. It's the same thing that happens with dirty battery terminals. You can measure 12 volts, but as soon as you try to start the vehicle, there is no current and voltage drops to zero.
I'm glad you found the splice. Am I understanding it correctly that the splice was between the fuse and the switch? There sure is no splice shown in the schematic. Did you mean that you think the previous owner added the splice?
EDIT: BTW, the reason the work lights were okay is that below relay K9, there is a wire (HM-50) shown going to the right off the page. I bet if you look at your other schematic page, you'll see that goes to fuse #7 or some other fuse. It seems New Holland really flipped these functions for the fuses between the "D" and "DA" models.
I'm glad you found the splice. Am I understanding it correctly that the splice was between the fuse and the switch? There sure is no splice shown in the schematic. Did you mean that you think the previous owner added the splice?
EDIT: BTW, the reason the work lights were okay is that below relay K9, there is a wire (HM-50) shown going to the right off the page. I bet if you look at your other schematic page, you'll see that goes to fuse #7 or some other fuse. It seems New Holland really flipped these functions for the fuses between the "D" and "DA" models.