Heated O2 sensor upgrade question. Is there a fuse?

[Alaskaburb]

I have searched and can't seem to find the answer. My burb only has a 1 wire oxygen sensor now. I will be adding a 3 wire oxygen sensor and don't know if it is fused or not. I have only found a thread that said a fuse was not needed. That goes against everything electrical unless the heating element by design burns out before the power wire does. Any help or direction to links would really be appreciated.

 

[someotherguy]

On the convenience center under the dash there are terminals that are hot only when the key is "on" (run position) - these are marked WHT. They are fused by the 4WD fuse which is 25A. You may want to take a test light and confirm as my memory is a little fuzzy; there may also be some terminals marked WHT that are only hot when the park/headlights are on, though typically those are marked GRA. Easy enough to tell them apart with the test light.

Anyway that's the circuit that the factory heated O2 is powered on, if you had a new enough model to come with it - like a light duty '94/automatic.

Richard

 

[Alaskaburb]

Thank you for taking the time to reply! I went out and checked and the ones marked WHT are always hot. I found one marked ORN ( old eyes so not sure) that is switched. Could that be the one? I need to take a light and my readers next time I go out there

 

[twomanymontes]

Always use a fuse. Heaters will short and cause wires to melt.

 

[someotherguy]

Thank you for taking the time to reply! I went out and checked and the ones marked WHT are always hot. I found one marked ORN ( old eyes so not sure) that is switched. Could that be the one? I need to take a light and my readers next time I go out there

Be sure you're looking at the correct markings. The terminals are marked to the right. Notice the very last column has markings although there are no more terminals, and the very first column has no marking to the left? See in this pic where I have the yellow wire with blue crimp terminal plugged in? That's a WHT terminal, only has power with the key ON, and it's for my transmission temperature gauge:

You must be registered for see images attach

Richard

 

[77Impala]

What is the benefit of converting our trucks over to the heated 02 sensor?

 

[twomanymontes]

What is the benefit of converting our trucks over to the heated 02 sensor?

Quicker fuel control for the computer. the sooner the O2 sensor starts working the sooner the computer is able to control the fuel mixture for better economy and performance.

 

[Alaskaburb]

Thanks for the replies. 77Impala as for my reasoning for the upgrade - I don't think my suburban will spend a lot of time warm enough so the one wire oxygen sensor can work. I have a 3 inch exhaust and my rig will be in Alaska and spend a lot of time on very short trips. The theory goes with a heated oxygen sensor the computer will/can adjust the fuel air mixture fairly quickly after starting. When the O2 sensor is not up to temperature the computer locks in a rich fuel mixture. Ever noticed the rich fuel smell when you first start your truck? The heated sensors became standard in 1994 on most vehicles and increases fuel economy and reduces emissions. Well there you have it. Thats my total knowledge of the subject.

 

[77Impala]

Ok thanks