oliver28472
Veteran Member
Is there a way to diagnose if the sender is telling the truth? I know I could plumb in a gauge. Any other suggestions?
Oil pressure idiot light
- Thread starter oliver28472
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Soundguy
Old Timer
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- RK 55HC,ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC
It is a switch.. probably ( NC ) closed to provide a dash lamp when key is on. Use a test lamp.. hook one side to power, put the probe on the sender spade if it is a single spade job. Lamp should be on when tractor is off.. and lamp should go off when you start and oil pressure comes up. If not.. sender is bad or you have no oil pressure.
You can take the wire off and ground it and your dash lamp should light if that circuit is working.
If it is a 2 wire job.. it may function as an inline switch.. don't see too many o fthose.
Soundguy
You can take the wire off and ground it and your dash lamp should light if that circuit is working.
If it is a 2 wire job.. it may function as an inline switch.. don't see too many o fthose.
Soundguy
PILOON
Super Star Member
I can think of only 2 ways.
Replace the pressure transmitter switch which may or may not confirm a problem.
or:
Temporarily install a pressure guage which is relativly easy as the pressure transmitter generally is a 1/8" npt which is what you'll use for the guage.
A pressure guage will be in the $10.00 ballpark area plus a fitting and some line. (If lucky and the transmitter is well located you could get away with a guage and a short length of 1/2" pipe)
The guage will give you an acurate reading over the entire rpm range while the idiot light is a simple 'go no go' device designed to only advise when you are under a specific PSI.
If you have low hours on the tractor it most probably is the transmitter so you could gamble and simply replace.
On a higher hr machine I would deffinately prefer to go the guage route as it would be a good diagnostic tool.
Replace the pressure transmitter switch which may or may not confirm a problem.
or:
Temporarily install a pressure guage which is relativly easy as the pressure transmitter generally is a 1/8" npt which is what you'll use for the guage.
A pressure guage will be in the $10.00 ballpark area plus a fitting and some line. (If lucky and the transmitter is well located you could get away with a guage and a short length of 1/2" pipe)
The guage will give you an acurate reading over the entire rpm range while the idiot light is a simple 'go no go' device designed to only advise when you are under a specific PSI.
If you have low hours on the tractor it most probably is the transmitter so you could gamble and simply replace.
On a higher hr machine I would deffinately prefer to go the guage route as it would be a good diagnostic tool.
ToadHill
Elite Member
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When I've worked on older equipment that have had sending unit problems, I have always run a T after removing the sending unit. I put a new sending unit into one leg and hook a pressure gage up to the other leg. I like to see what my pressure is and the Light always attracts my attention if something goes bad.
OP
oliver28472
Veteran Member
Thanks to all. This is for a neighbors tractor. I will pass along.
normde2001
Elite Member
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I always thought a gauge took a "variac"/variable type sender and an idiot light took a "switch" type sender. How are guys able to "T" off the same sender and use both?
Soundguy
Old Timer
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- RK 55HC,ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC
I'm sure he meant that the oil fiting inthe block was tapped with a "T" adapter, then both an idiot light and gauge sender wre plugged into either side of the T fitting so that both had access to the oil pressure.. etc..
Soundguy
Soundguy
OP
oliver28472
Veteran Member
That's my understanding too. Anyway, my neighbor did call Valley Power, got a new sender and that fixed it. One of my tractors has had a gauge added and I think the other will soon.