Another oil pressure gauge question

[British Slave]

Does anyone have a Blazer with factory gauge AND idiot light? My Blazer has a factory gauge, but it has the two wire sending unit for a light. I can't look to see if I have a light, never paid any attention to it before, the Blazer is 170 miles away at home. I didn't think any thing about the two wires till I went to buy a new sending unit today and the gauge unit is a one wire and the light unit is a two wire.

 

[dyeager535]

You are probably mistaking that for the electric choke oil pressure switch, which IS two wires.

 

[British Slave]

This one. This is the one Auto Zone shows for oil pressure with light. It's an 87 with TBI.

 

[British Slave]

This is one for gauge.

 

[dyeager535]

The last pic is definitely the old school sender, but from everything I've seen those ended about '90, when the three wire was used.

Here's my three wire.

Hard for me to tell, but I'm assuming I can't quite make out that connector in your first pic...it's two wire, isn't it? Which means it's just a switch as you said.

I'm gonna say the parts websites are wrong. I checked napaonline (click page 7 on this link, towards the bottom, here: http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=430&CatId=15&SubCatId=4 ) and they say oil pressure light switch, but list the fuel pump switch as the same part. Likely a misunderstanding of what they really are, or to help people that don't know better to find it. They could easily be used to switch a bulb, but that's not what they are. I've never seen the '87+ two wire fuel pump switch, but I bet GM went with the newer plastic switch body instead of the older metal choke switch. Also changed the connector but little change in actual function. if you play around with the other links, you'll find the metal idiot light switch style on the same page.