305 temp sending sensor location

[k5ryder]

My temp gauge isn't working on my 85 blazer with a 305. I was thinking of replacing the sending unit. Can anybody give me a location on it please? Also, is the temp sending unit also known as a coolant temp as sensor or are those two different things?

 

[British Slave]

Temp sender is located on the driver side head, next to the exhaust manifold. I'm not familiar with 85, but the coolant temp sensor is probably located beside the thermostst housing if it has one.

 

[dyeager535]

What is the guage doing? The senders do fail (not often, but they do), but there are other causes that won't cost money to fix.

 

[k5ryder]

It just says its cold all the time. I just bought the blazer this weekend.

 

[80' 427]

Bet it is unplugged. Look at the one by the drivers exhaust manifold.

 

[k5ryder]

Well the sending unit was hooked up and not working. I replaced the sending unit and it still isn't working. Where does the green that is connected to the sending unit go?

 

[diesel4me]

It goes to the gauge,its the ground source to operate it...if you take the wire off and ground it,with the key on,the gauge should peg to full scale if the gauge and wire are good...dont leave it grounded too long or it might damage the gauge...the sending unit is just a variable ground thats heat activated,the hotter the coolant gets the less resistance it has,and the higher the gauge reads..

 

[k5ryder]

The gauge does not peg to full scale when grounded. Would it be hard to run a new wire to the gauge? Also when I turn the key in the ignition to the on position the gauge goes from 100 degrees to 90 degrees. In other words it basically flinches to a cooler temperature.

 

[dyeager535]

Stop. Diagnose the problem, don't try to bandaid it or swap/buy new parts. It's a waste of time and money.

The problem isn't likely the wire. It's probably going to be the connection to the gauge, cluster, or something along those lines. Until you can get at the end of the wire to check it for continuity, you don't know where the problem really is, except it's not the sending unit.