2 tanks to 1, gauge issue

[Dirty 30]

I have an 80 k10, I pulled out the 2 saddle tanks and put 1 in the rear, new tank and sending unit, with key off it looks like I have the correct reading and when I turn the key on, gauge pegs way past full. Help
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[cse]

Does your truck still have a switch to change between the dual tanks you removed? If so, what happens to the gauge when you move the rocker switch?

[Dirty 30]

Originally Posted by cse

Does your truck still have a switch to change between the dual tanks you removed? If so, what happens to the gauge when you move the rocker switch?

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[Dirty 30]

Originally Posted by Dirty 30

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My truck still has the switch, I haven't touched that, I doesn't do anything when switched back and forth, do I have to get rid of the switch?
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[cse]

No, you shouldn't need to take out the switch. Where did you wire the new sending unit to?

My truck is a 74 with a mechanical switch. After the tank swap, my gauge would either go way past Full or be accurate, depending on which position the tank switch was in. In my case, it was a simple wire swap at the bulkhead connector to get the fuel gauge to read correctly when the switch was pushed in.

[Dirty 30]

Originally Posted by cse

No, you shouldn't need to take out the switch. Where did you wire the new sending unit to?

My truck is a 74 with a mechanical switch. After the tank swap, my gauge would either go way past Full or be accurate, depending on which position the tank switch was in. In my case, it was a simple wire swap at the bulkhead connector to get the fuel gauge to read correctly when the switch was pushed in.

I used one of the original sending unit wires, extended it to the new tank
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[100%Chevy]

Your old right side tank is considered the default circuit.
If your using the left side wiring,it may not work correctly.
On my 82,a pink with black stripe is the left and the pink with white stripe is the right.
The problem may be the old switching valve on the frame is not moving enough to change the guage.You might want to bypass the valve wiring and switch and go directly to the guage
Mike.

[Dirty 30]

Ok, thanks
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[Dirty 30]

Originally Posted by Dirty 30

Ok, thanks
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I have the Cluster out, what wire would I connect to on back of the panel?
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[100%Chevy]

If you mean me,I don't know right off.
I can look in my books tomorrow when I get back to the shop.
This info is on-line if you can find it.
O.K.,I looked here---

https://www.google.com/search?q=1980...D2LUp2ba9x0KM:

Looks like pink 30 to the bulkhead connector(firewall connector) and a pink to the cluster connector on the back of the instrument panel.
Mike.