1989 4.9 and the temp gauge is not working. Is the engine temp sensor bad or is it the sender? How do I replace the sender.

 

The Sender. With a wrench or socket, after disconnecting the wire connector. It's a stubby lil b*stard compared to the ETC sensor & w/o the plastic connector. Google (images) Coolant temperature Sender! Don't own the manual for your truck?

 

Not the original but I do have a haynes

 

Works now after replacing SENDER.

 

Having same problem, since I've bought the truck. I know its the sender, but I can't find the damn thing. One person on here told me it was on the back of the block straight up from the starter, but in my Chilton's manual it shows it on a 4.9 somewhere near the fuel injectors (it just has a little arrow and is a picture of the entire engine). I understand I'm looking for one wire coming out of it, but I can't find this damn thing. 1992

 

Try on the drivers side,just below where the air intake bolts on, all the way to the front, into the block.

 

Found something near that location...one wire sensor, mounted in block near where oil dipstick enters block and oil filter. I've had a long term oil leak in this thing and its kinda hard to tell exactly what this thing would look like if it was clean. I looked up the temp sender on ebay and its about the same size... Sound about right?

 

No wrong side. Ill send you the link to a picture.
https://www.f150forum.com/f10/removi...1-4-9-a-22285/

 

Id also suggest grounding the wire before replacing the sender to check if the problem is the sender or the wire. If you ground the wire connector with the key on engine off the needle should go all the way to the right. If it does not then the wire connector or something else other then the sender is the problem

 

Ok thanks for the help. Now that I look at the big picture, the chilton's picture seems a little more accurate. I wish they would've just included your picture to begin with. The problem with these manuals is that they cover the bronco and other f-series with all the different engine setups and they aren't able to give enough attention to just the motor that the owner has. Oy.