oil sender question

[Rajk]

as i understand it there are two oil senders on a valver/willy, for the oil guages, my dipstick guage works fine, but my temp and pressure dont work. Where are the senders located? how much do they cost? and which ones do what? any help appreciated!

 

[BenR]

pressure is at the back of the block, cylindrical looking thing.

Oil temp is about 10 o'clock from oil filter.