Black1990jeep
NAXJA Forum User
- Location
- california
On my 1990 Renix Inline 6 I am trying to understand the O2 sensor circuit for trouble shooting, I have the factory schematic. The O2 sensor heater relay is a single pole, double throw type as seen on sheet 20 of the schematic. One throw terminal goes to the O2 sensor heater and the diagnostic connector via an orange wire, and the other throw terminal of that relay goes to an orange/black wire that splices to the fuel pump.
So when the O2 heater relay is switched one way the power goes to the fuel pump circuit, and when that relay is switched the other way the power goes to to the O2 sensor heater.
Why is this O2 relay hooked up like that, when the O2 heater is on the relay is closed to the heater ( which makes sense) but when the relay turns the heater off, that relay is connected to the fuel pump circuit. that makes no sense to me, what am I failing to comprehend here?
Thanks!:bunny:
So when the O2 heater relay is switched one way the power goes to the fuel pump circuit, and when that relay is switched the other way the power goes to to the O2 sensor heater.
Why is this O2 relay hooked up like that, when the O2 heater is on the relay is closed to the heater ( which makes sense) but when the relay turns the heater off, that relay is connected to the fuel pump circuit. that makes no sense to me, what am I failing to comprehend here?
Thanks!:bunny: