What is an "A/F HTR" and why does the car run fine w/o the 25A fuse?

[ladd2]

I'm starting to go over the smaller details of the newly acquired 2000 Camry CE with 105K and one puzzle originates in the engine compartment main relay/fuse block:

The car is missing a 25 amp fuse in the slot for the "A/R HTR". The owner's manual says that this is for the "A/R Sensor".

What is an A/R HTR and an A/R Sensor?

If it is important, how is my car apparently running fine without the 25 amp fuse in place?

Any interesting reasons as to WHY there is might not be a fuse in that slot; i.e. if I stick a 25 amp fuse in there, might there be a possibility of great excitement, flames and noise?

[JerryR]

A/F stands for Air/Fuel, this is the sensor also known as an "Oxygen sensor" this sensor contains a heating element.
The fact that the fuse panel does not have a fuse in this position might be meaningless, since the fuse panel may be a holdover from another year/model.
HTH
JerryR

[ladd2]

Originally Posted by JerryR

A/F stands for Air/Fuel, this is the sensor also known as an "Oxygen sensor" this sensor contains a heating element.
The fact that the fuse panel does not have a fuse in this position might be meaningless, since the fuse panel may be a holdover from another year/model.
HTH
JerryR

Thanks for the reply!

I am familiar with oxygen sensors, having replaced both of the ones on my 1996 Camry. I somehow must have not become familiar with the abbreviation A/F sensor and A/F heater during that process.

An excellent point to consider re: the possibility that the fuse box and lid markings possibly not being accurate for my particular car. However the owner's manual show the 25A A/F heater fuse also, so it apparently confirms that I'm supposed to have a fuse there.

[brief time out to go out and inspect the fuse area closely]

So much for fuse box lid and owner's manual equalling confirmation.

Close inspection of the slot where the 25A A/F Heater fuse is supposed to go reveals that the slot is blank -- there are no metal contacts down at the bottom to accept the blades of the fuse .As metal contacts can clearly be seen down at the bottom of the several other fuses I pulled to check, I'm going to go with your original idea that the fuse case cover markings AND the owner's manual are incorrect.

Actually a bit unsettling considering that I had always considered those items accurate and to be relied on in situations where I really didn't know what I was doing ...

Thanks for your help and for your "out of the box" advice (for me) turning out to be the solution!

Ladd