tiggercl 28 #1 Posted November 24, 2012 Chaps, Can anyone advise as to the correct Onan part number for a 2 terminal oil pressure switch (see pics). Onan engine spec is P220G-I/10955D Cheers. Paul Share this post Link to post Share on other sites
dbartlett1958 99 #2 Posted November 24, 2012 I believe you want 309-0641-18, which was superceded by 309-0105. Share this post Link to post Share on other sites
tiggercl 28 #3 Posted November 24, 2012 Thanks for that ! Paul Share this post Link to post Share on other sites
dbartlett1958 99 #4 Posted November 24, 2012 Paul, I edited my post to add a pic. David Share this post Link to post Share on other sites
tiggercl 28 #5 Posted November 24, 2012 Super ! Paul Share this post Link to post Share on other sites
tiggercl 28 #6 Posted April 15, 2013 Super ! Paul Not so super... 309-0641-18 does not work correctly as the terminal is normally open... Can anyone advise as to the correct switch? Paul Share this post Link to post Share on other sites
soofoodude 6 #7 Posted August 13, 2016 Old thread - thought I would update. Normally open is what my parts book says for my model. Share this post Link to post Share on other sites
cleat 7,263 #8 Posted August 13, 2016 The two terminals are NO and NC as related to ground. One of them is NC and grounds out with no oil pressure to turn on the oil pressure light. With oil pressure present, the terminal open and the oil light goes out. The other is NO and grounds out with pressure present to complete the circuit for the Hour meter. With no pressure as in with the ignition switch on and engine not running the Hour meter does not run. If you wire this switch backwards, the Hour meter will only run with the key on and engine not running and the oil light will come on with the engine running. This is how my 520's are wired. 1 Share this post Link to post Share on other sites
