Author Topic: 75 D21 fuel gauge not working  (Read 198 times)

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Offline YYC403

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  • Year: 1975
  • Make: Winnebago
  • Model: D21 Brave
  • Chassis: Dodge
  • Engine: 440-3
75 D21 fuel gauge not working
« on: April 24, 2021, 03:40 PM »
So I'm working towards fixing things on my new to me '75 D21 Brave, one issue being the fuel gauge not working.

I've read through previous threads on here and the 73-75 fuel gauge troubleshooting document that's in the full members section and where I'm at is I had the mechanics take a look at it and they think it's a faulty gauge.

So I purchased a new gauge and today have been trying to pop the instrument cluster out but that's kind of a Bugger as it doesn't want to come forward due to the vacuum gauge connection I think.

I contorted my body under as best I could, I see what looks like a 2 pin connection with cardboard and tape over it, looking in the wiring diagram is this for a choke?

I don't see any light blue L shaped connector wire for the fuel sending connection, there is 2 wires capped with electrical tape just hanging nearby, one is black the other is red... Not sure what they're for.

Thinking nothing is even hooked up to the gauge? Attaching a few pics for reference, any insight would be appreciated.

Offline Elandan2

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Re: 75 D21 fuel gauge not working
« Reply #1 on: April 25, 2021, 06:55 AM »
The fuel gauge wire will be on the plug on the back of the instrument cluster. The gauges operate through that copper circuit board in your picture. Replacing the gauge is simply a matter of undoing those two nuts and taking the gauge out of the front of the cluster.
Rick and Tracy Ellerbeck

Offline YYC403

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  • Year: 1975
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  • Model: D21 Brave
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  • Engine: 440-3
Re: 75 D21 fuel gauge not working
« Reply #2 on: April 25, 2021, 04:15 PM »
I got the cluster out after finaggling with what was keeping me from easily pulling the cluster out a bit, the lights connector thing was snagged on the dash pretty good.

There's no blue wire or anything hooked to this gauge area from what I can see, is the 2 prong connection supposed to be where the sender connections are to be attached?

There's 3 wires floating around so I'm wondering if it's them?

Offline YYC403

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  • Posts: 13
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  • Year: 1975
  • Make: Winnebago
  • Model: D21 Brave
  • Chassis: Dodge
  • Engine: 440-3
Re: 75 D21 fuel gauge not working
« Reply #3 on: April 25, 2021, 05:39 PM »
Does the sending unit wire send any resistance while the unit is fully powered down/not in accessory mode?

Just wondering as one of the wires was sending 12.x ohms while the unit was fully off. Had just filled the primary tank and had a 20 minute drive home when I last drive it so perhaps is showing slightly under full?

Wouldn't show any volts from this wire when I changed the mode on my multimeter to voltage

Offline YYC403

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  • Year: 1975
  • Make: Winnebago
  • Model: D21 Brave
  • Chassis: Dodge
  • Engine: 440-3
Re: 75 D21 fuel gauge not working
« Reply #4 on: May 02, 2021, 09:15 PM »
Got this sorted earlier in the week.

Ran a wire from the light blue wire connection that goes into the 8 wire connector on the back of the instrument cluster and then power and ground to the autometer gauge I bought.

Glad to have a working fuel gauge now.

Offline Oz

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Re: 75 D21 fuel gauge not working
« Reply #5 on: May 02, 2021, 09:18 PM »
 :)  :)ThmbUp