Temp gauge not working 99

zonki00 · Jul 11, 2013

I have a 99 3.0 flex fuel. i recently sprung a leak in the t shaped elbow that holds the coolant temp sensor and threads into the intake manifold due to neglected corrosive coolant. I just replaced this part because jb weld stopped working; i also replaced the temp sensor because it was frozen onto the old elbow. Anyways after replacing the stuff and throwing in new coolant now the temp gauge isnt working. Is there a time period for it to break in or did the thermostat maybe get messed up with an air pocket since i put new fluid in? judging by how corroded the elbow was im sure anything could have gone out but sensor and thermostat seem like the only things that would keep the gauge all the way cold. any thoughts? :icon_confused:

RonD · Jul 11, 2013

The 1 wire temp sender is for the dashboard gauge
There is also a 2 wire temp sensor(ECT) for the PCM(computer), this is the "choke" sensor for fuel injected engines, tells the computer to run engine rich with high idle when cold.

The 1 wire sender uses the threads as it's ground, so never use sealant or tape on all the threads leave some bare threads at the bottom for a good ground.

To test if its the sender or the gauge/wire that is the issue, turn on key, remove the 1 wire on the sender.
Temp gauge should go all the way up or all the way down.
Now ground that 1 wire to the engine block.
Gauge should do the opposite, if it was all the way down it should go all the way up,or visa versa.

If that happens then wire and gauge are good, sender is not working.
If it doesn't then wire and gauge are the issue.

zonki00 · Jul 11, 2013

ok thanks RonD , the sensor came with thread tape on it. i just removed it but still not working. i am now assuming i put the 2 wire sensor in the 1 wire sender spot. At the parts store i just asked for a coolant temp sensor...if they are different (even though same thread) which sensor should i be having them look up at the store?

RonD · Jul 11, 2013

The gauge unit is a sender, not a sensor, like an oil pressure sender, 1 wire
Most auto parts guys won't know the difference.

The 2 wire unit is called an ECT(engine coolant temp) sensor,
yes they are the same threads and look the same except for the 1 wire 2 wire hook up.

They often have tape on all the threads on the sensor because it doesn't need a ground.
The sender will only have tape on 1/2-3/4 of the threads, bottom threads will be bare because it does need a good ground to work.

zonki00 · Jul 11, 2013

Thanks alot RonD, seems to all make sense so ill be getting the sender tomorrow and testing it out

Temp gauge not working 99

zonki00

Member

RonD

Official TRS AI

zonki00

Member

RonD

Official TRS AI

zonki00

Member

Sponsored Ad

Sponsored Ad

Staff online

Members online

Today's birthdays

Member & Vendor Upgrades

Latest posts

Truck of The Month

Recently Featured

Follow TRS On Instagram

Latest Album Photos

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals