Oil pressure sensor wiring on 3800 SC (Page 2/2) MulletproofMonk APR 26, 08:38 PM quote Originally posted by olejoedad: The backup fuel pump power circuit is not wired per you info, Brian. Pin A does indeed go to C203 E for the gage. C and D go to C203 B and L. Well, that is interesting, because that is what i have on my sheet... i did a strike on it to not spread the wrong information... olejoedad APR 27, 08:10 AM TurboGN APR 27, 09:06 AM Thanks for all the great information guys. I pulled the oil pressure gauge and followed the Tan wire which ends at the C203 as a Whiteish wire (maybe color change due to age?) that is in the "C" pin with no wire on the opposite side. I spliced into that wire but still had a pegged gauge. I switched to a 1988 oil pressure sensor and it now works. I seem to think that I am going to be running into this kind of stuff on the last two items, A/C & Cruise control. olejoedad APR 27, 11:40 AM quote Originally posted by TurboGN: Thanks for all the great information guys. I pulled the oil pressure gauge and followed the Tan wire which ends at the C203 as a Whiteish wire (maybe color change due to age?) that is in the "C" pin with no wire on the opposite side. I spliced into that wire but still had a pegged gauge. I switched to a 1988 oil pressure sensor and it now works. I seem to think that I am going to be running into this kind of stuff on the last two items, A/C & Cruise control. The 'C' pin on the C203 is for the malfunction indicator light in the instrument cluster. The 'C' pin on an 88 OPS is for the fuel pump relay backup circuit. The 'A' pin on the 88 OPS should be attached to C203 on the 'E' terminal. Are you sure your posting doesn't have a typo error in it? TurboGN APR 27, 09:25 PM quote Originally posted by olejoedad: The 'C' pin on the C203 is for the malfunction indicator light in the instrument cluster. The 'C' pin on an 88 OPS is for the fuel pump relay backup circuit. The 'A' pin on the 88 OPS should be attached to C203 on the 'E' terminal. Are you sure your posting doesn't have a typo error in it? You're right, it should be "D" not "C", and there was no wire coming out.