Hi Kid, I also have a 48 gmc 1/2 ton. When I got my truck the wires to the temp sending unit were cut and it is electric as you say. It looked like the original sending unit but when I tried to find a replacement sending unit and gauge I could not. So when I replaced my gauge cluster I had to go with the mechanical kind so I changed mine over. It works great and it seems that everyone I’ve seen runs the mechanical type. Good luck!
Thanks for the comments. Yes it is in the factory round housing for the gauge cluster and there was a electric sender although it was at the front of the engine not in the manifold. The gauge housing has a round hole behind the temp gauge unlike the oil pressure gauge which is square to hold it in position while tightening the line to it. The back of the replacement gauge I bought (which obviously is mechanical ) is square like the OP gauge. I don't have a problem using the mechanical gauge however I will have to modify the housing to accept it. Was yours this way Jim K? I imagine that my current gauge can be restored. I'm not sure if it works but the needle has broken off. That's why I wanted to replace it. Rob
Hi Rob, I put the new sending unit in the same place as where my electric one was. Not sure if this is factory or not but all I had to do was get a special reducer, the kind with a retaining edge to hold the new sending unit so the nut would put pressure on the probe when tightened down. I’m going to upload a pic to help you out if yours is the same as mine. Good luck!
Well Rob, I cant really help you with the gauge in the cluster since I bought the whole gauge cluster already restored with new gauges for 12v. As far as the housing It’s just remove the wiring and the 4 nuts that hold it and then replacing with the new. Sorry I couldn’t be more help, good luck!
Jim K I already have the gauges out. I removed them when I rewired the truck. I was actually more curious than anything if anyone could prove /disprove if they used electric as well. My gauge and housing appear original. You said your old gauge was electric as well so maybe they did? I just found it interesting. Thanks for the input. I've also found more proof that wherever you go on social media the trolls will find you. ...