Extra Bulkhead ?

[Roadguy]

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Hey everyone New here!
My son bought a 75 c10 small block 350. After some investigation the vin says the cab is a 75 k10.
I’ve searched everywhere and haven’t came up with a definite answer on what the bulkhead to the left of the main one is. Can someone guide me In The right direction??
The previous owner had wrapped all these wires up in the wire loom and none of them connect to anything.

 

[Matt69olds]

Dual tanks? I wouldn’t think a 75 model year would have any kind of computer. Auxiliary lighting for camper shell? Are there any connectors left on the wire ends?

 

[Charlie]

 

[78C10BigTen]

Dual tanks? I wouldn’t think a 75 model year would have any kind of computer. Auxiliary lighting for camper shell? Are there any connectors left on the wire ends?

Im pretty sure that has nothing to do with dual tanks. My 78 c10 has duals and im 95% positive it dont have that bulkhead

 

[hatzie]

That's something a previous owner installed... They did a nice job. Usually people aren't as diligent about removing things inside the cab. Where are the wires on the interior side of that bulkhead plug routed?

NL2 dual tanks would be a round rubber overmolded four position connector/grommet similar to the taillamp disconnect at the back end of the LH frame rail.

 

[Roadguy]

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Thanks for the replies guys. This truck has been a nightmare full of surprises.
The truck does have dual tanks. My first thought was diesel but the vin number is throwing me off of it being that. All the pictures show where the wires go except 4 of them go up to the dash somewhere.

 

[CorvairGeek]

The complexity of the module and number of wires suggest cruise control to me. Can't say I've looked at one of the vintage. Although, I could see that looking like a glow plug controller too.
The switch above the accelerator pedal is the downshift switch for a Turbo 400.

 

[Roadguy]

The complexity of the module and number of wires suggest cruise control to me. Can't say I've looked at one of the vintage. Although, I could see that looking like a glow plug controller too.
The switch above the accelerator pedal is the downshift switch for a Turbo 400.

I’m not sure where the factory cruise control switch would be. Nothing has been original on this truck so far.There is not any switch on the column for cruise control. Is that where it might be?
At least I know what the switch is above the accelerator.

 

[CorvairGeek]

Single switch out on the end of the turn signal stalk that pushed in to set the cruise on a factory system of the era. The word 'Cruise' typically wore off. Aftermarket typically had a little slide switch too out on the end of the turn signal stalk.

 

[Roadguy]

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Single switch out on the end of the turn signal stalk that pushed in to set the cruise on a factory system of the era. The word 'Cruise' typically wore off. Aftermarket typically had a little slide switch too out on the end of the turn signal stalk.

I definitely don’t have anything on the steering column or the signal switch. I’ve looked in google images for an hour trying to find this module. But no results. I’d think this module would definitely identify what the bulk is..

 

[DanMcG]

No Identifying names or numbers on the case?

 

[Roadguy]

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No Identifying names or numbers on the case?

Just the letters A to N is all I see.

 

[Rickf]

Could the cab have been a diesel in a past life?

https://www.gmsquarebody.com/threads/location-of-the-glow-plug-control-card-on-a-cucv.18783/

 

[Roadguy]

Could the cab have been a diesel in a past life?

https://www.gmsquarebody.com/threads/location-of-the-glow-plug-control-card-on-a-cucv.18783/

This was my thought too. Were there diesels in 1975 or was the first ones in 78? The vin reads 75 and doesn’t appear to be tampered with.

 

[Rickf]

Those rivets can be purchased. There may be numbers on the frame that match the last bunch of the VIN. Get a wire brush and look, try the pass side first. My 84 M1009 had that style controller, I can check under the hood tomorrow.

Was the 5.7L Olds diesel available for squares? Answered http://www.dieselhub.com/idi/5.7-olds-diesel.html my own question.