oil pressure switch hookup

[13crazyhorse]

I recently purchased an aftermarket oil pressure switch for my 2002 4.3 mercruiser part #87-864252A01. The old unit has two wires purple (alternator/harness} and purple/yellow fuel pump, electric choke, starter. The new switch has a red and a black wire. How do I know which one goes where? thanks for any help.

 

[Rick Stephens]

Have to read the directions on the switch. All oil pressure switches that I have seen have terminals, not wires.

 

[13crazyhorse]

Unfortunately there are no directions and the wires are not marked with anything.

 

[13crazyhorse]

I'm thinking it wouldn't make a difference since I've been told if you hook the two wires together is bypasses the switch anyway?

 

[Rick Stephens]

I'm thinking it wouldn't make a difference since I've been told if you hook the two wires together is bypasses the switch anyway?

From a cause/effect standpoint, that is not a workable conclusion. However, any 2 wire pressure switch should not care which side is battery power and which is pump side. I still cannot imagine finding one that has wires and not terminals. Are you sure it is a pressure switch and not a pressure sender?

 

[achris]

I'm thinking it wouldn't make a difference since I've been told if you hook the two wires together is bypasses the switch anyway?

Correct. A switch doesn't care which way the current flows. But as Rick suggests, there may be more to this post that meets the eye. Can you post a photo of the 'switch'?

Chris....

EDIT: Just checked the parts diagrams, that is the right oil pressure switch (to run the fuel pump) for your engine.. In future, please post (full) engine serial number. It was a pain working through 3 different files to get a serial number range for your 2002 engine, then assuming it was a carbed engine, given an MPI wouldn't have that switch, then finding the right parts breakdown...

Cheers.

 

[Yegboats]

Correct. A switch doesn't care which way the current flows. But as Rick suggests, there may be more to this post that meets the eye. Can you post a photo of the 'switch'?

Chris....

EDIT: Just checked the parts diagrams, that is the right oil pressure switch (to run the fuel pump) for your engine.. In future, please post (full) engine serial number. It was a pain working through 3 different files to get a serial number range for your 2002 engine, then assuming it was a carbed engine, given an MPI wouldn't have that switch, then finding the right parts breakdown...

Cheers.

Serial number? Why need a serial number it's just a Chevy engine I love hearing that as a parts person.

 

[13crazyhorse]

ser#0M087992

 

[Rick Stephens]

Learn something every day - (or you're dead)

 

[achris]

ser#0M087992 + picture

Right... Thanks for the picture. I suspect that the wires are part of a plug that you could pull off that switch and it would have a couple of posts, just like the old one...

Chris...

 

[13crazyhorse]

Not so with the posts. There are small pins. I'm just gonna hook it up and see what happens. If the boat blows up it will save me alot of money in the future. (only kidding of course).