# Ford 6610 (Main Diesel Tank) Sender Unit



## rob4465 (Mar 13, 2021)

I have been restoring my late father's Ford 6610 as I plan on using it this year to do some baling. The annoying thing is that the fuel gauge is not working correctly. This model has a primary tank and an auxiliary tank. When the ignition is turned off the fuel gauge shows half full, however when the ignition is on the gauge shows empty.

I was wondering if anyone has managed to ever replace the primary fuel tank sender without splitting the tractor for a bigger job? The auxiliary sender is easy enough to access and I have tested its resistance. The primary one appears to be hidden away very well and it looks like it goes beneath the dashboard some way. I have loosened the top cover of the dash to inspect it but it doesn't look like the top of sender is visible.

Has anyone managed to access this?


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## sixbales (May 18, 2011)

Hi rob4465, welcome to the tractor forum.

Does the parts diagram below represent your dual tank setup??

New Holland 6610 - 4 CYL AG TRACTOR 10 SERIES(01/81 - 12/93) Parts Diagrams


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## sixbales (May 18, 2011)

Post Deleted - Incorrect information.


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## Hacke (Feb 22, 2011)

I know nothing about that tractor, but I have some documents (So do you, sixbales 😉). The files are unfortunately too large to upload to this forum.

I attached a page from a Repair Manual for the 10-series.
At another place in the manual, it says that old manual information was reused, where applicable. So, 6600 instructions concerns 6610 instructions on this page.
According to this instruction, the fuel sender can be removed through the dash instrument panel opening.

Looking at parts lists gives that the sender was fastened with screws from 12/1983.

I have an Operator's Manual (in Swedish) that says that the fuel gauge shows a value that very well can show a higher level than the actual level, when the key is off. The temperature gauge shows a random value when the key is off. It also says that the low fuel level warning light goes on when there are less than 18 L left in the two tanks together.

*** Edit
Attachment added.
***


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## rob4465 (Mar 13, 2021)

Thanks sixbales and hacke for your replies / documents - much appreciated. I have answered my own question in the end. Hacke, your instruction page is indeed correct. I took a closer look at it this afternoon. If you take off the instrument cluster and unscrew the RPM drive cable the cluster will pull out to open up the space behind. Now, with the instrument cluster out out of the way you will see what looks like a blanking panel (on the right) with 2 screws and a bolt. It's fairly straight forward to get these out and using a screwdriver blade the panel will lift up. On mine there was some insulation directly underneath. I cut this away and it revealed the fuel sender unit on top of the main tank. It was the locking ring type which I will remove in due course. I have ordered a replacement unit. Once I fit it I will upload some more images here. Thanks again.


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## rob4465 (Mar 13, 2021)

Just to update you on this.. I have now replaced the sender unit. The old one had definitely had it. Interestingly, unlike the auxiliary sender unit (which has a separate earth cable) the main one goes to earth through the locking ring, as far as I can tell. The gauge is still not working correctly so I will continue to look into it and report back once I have a resolution. I've put some images below so you can see the blanking plate that covers the sending unit. Thanks again all for assistance.


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## Hacke (Feb 22, 2011)

I have been looking at some documents, and it seems like your setup is like the one on 6600. After 1985 there were changes done to 6610 and there are different wiring solutions depending on market, cab type and more. What year is your tractor?
Is the cab floor a flat deck or divided?

The solution with two tanks and a sender in both of them is the same as for 6600. I attach a wiring diagram for 6600 I found at maskinisten.net. I found it interesting that the two sender's signal wires are connected together. The two resistances are therefore connected in parallell, which has to be considered when you test the parts. There is also a shunt resistor at the gauge.

8 Fuel gauge
11 Shunt resistor
17 Instrument connector
35 Connector at the torpedo
47 Main fuel tank sender
51 Auxiliary fuel tank sender

LG/S Light green/Light gray
G/B Green/Black
LG/U Light green/Blue


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## rob4465 (Mar 13, 2021)

Thanks very much Hacke for the information in your last post. Just an update on this. I have replaced the main fuel tank sender unit which was required in any case. I have since replaced the auxiliary unit, which upon first inspection appeared to be ok. The resistance couldn't have been quite right. As mentioned by Hacke the two units are indeed connected in parallel and sensitive to any change. The fuel gauge now appears to work, although it shows a reading even when the ignition is off - something that Hacke had mentioned in a previous post. I'm not too concerned about this as previously there was no reading at all once ignition was on. As I work through the fuel I will keep a close eye on the gauge. It is worth noting that the instrument cluster has a number of resistors on the back of it, although I'm thinking it is less likely for this to go wrong and more likely for the sending units to malfunction as they're essentially moving parts and wearing. Hopefully this will help someone else if they come across it. Many thanks to everyone who has contributed as it's been a massive help!


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## rob4465 (Mar 13, 2021)

Just some info I forgot to answer. The 6610 is a Y plate which I think is 83 and the cab floor is divided.


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## Hacke (Feb 22, 2011)

That is great news. Your information will sure help others in the same situation. The 120 Ω "shunt resistor" at the gauge is probably there so the same gauge could be used for tractors with only one tank. It is good to know about it's existance when someone wants to measure the system.

The 6600 diagram is for tractors with cab and divided floor. It seems to work for this 6610 with divided floor. If someone have another cab/tank solution, perhaps it will not work.

Thank you, we have learned a lot from this problem.


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