2-105 warning lamps and fuel sender test

[Jake Collie]

Here's a dumb question, so please go easy on me. How does a person replace a warning lamp? (parking brake, trans oil pressure) Does the red plastic cover come off from the front of the dash or do you have to remove the dash and replace the lamp from the back side?
Also, can I test the fuel tank sending units with an ohmmeter from the sending wires at the gauge to ground (removed from gauge of course) or do I need to test the sending units at the units themselves? The gauge goes to full when I ground the sending lug and goes to empty when I remove the wires from the sending lug. Both tanks are full.
Thanks

 

[MikeO-WI]

I had a non-working fuel gauge on a purchased 2-105 that took a little bit to track down. There is a trick to how the wires are hooked up to make the connection between the two sending units. Someone provided a wiring diagram and I found the wire between the two tanks was missing. Ran a new wire and hooked it correctly and it worked. You might find the posts to my question in a search from mid year last year.

 

[Jake Collie]

Thanks Mike. Will do

 

[rvirgil_KS]

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Page 2 7/8/22 update on 2-105 gauges

 

[MikeO-WI]

I think the last two letters are extra. Just checked to see all my posts.

 

[MikeO-WI]

If I recall correctly, one of the two senders is not grounded and therefore there is a wire needed to run from one sender to the ground on the not grounded sender and then from that sender to the guage. It was a bit odd but I was surprised when I found the post that were used and ran a test or jumper wire. It worked.

 

[random_farmhick]

First thing first, if I remember correctly, the early ones, pre gravity flow, only had a sending unit on the top tank. If that s the case, testing is going to be different than the later ones. So which style do you have?

 

[Jake Collie]

Later style. Both tanks have senders.

 

[MikeO-WI]

Jake, I went out to the farm today and looked at the White 2-105 I worked on this past summer. The wire I ran to the lower tank connected to a blade type post on the outer ring of the sender unit. The post in the center of the sender unit has a wire attached to it but I never really tracked that one down. As best I could determine that wire connected to the frame of the tractor to provide the necessary ground to complete the circuit. As best I can tell, the lower tank is insulated from the frame so there is no direct grounding. Maybe someone with a little bit more knowledge on this can chime in. I can't remember what the connection was at the sender for the upper tank but this wire made it finally work. I have a picture and will try to load it up.

 

[Jake Collie]

Mike - FYI - The wire in your picture with the blade type connector should be an orange wire. It goes from where you have it connected up to the upper fuel tank sender and then on to the fuel gauge. The other wire in your picture should be a black and white wire which goes straight to the fuel gauge. I will have to do some checking on my wires for continuity when it warms up.

 

[random_farmhick]

Well this is what my service bulletin says for what they should test.

 

[Jake Collie]

Great information. Thank You