86 v6 motor dash gauge don't work. what I did to check by the manual, grounded wire from sending unit to dash, goes to hot.gauge and wiring to gauge good. checked sending with ohm meter, no reading from ether prong to ground.. got resistance from prong to prong.. had good sending unit base to block connection. so I and manual said bad sending unit, I order a aftermarket unit, and it reads the same, doesn't work ,so I contact them and they sent me another on, same, don't work..so I ordered a original ace high price. still don't work same reading all 3.. the manual shows power from switch to sender 12volts which I got. then going . in sender to ground.no reading, I put in boiling water and checked. got same reading nothing dash dash light go on and off with ing switch


WHAT AM I MISSING

MIKE

Gauge/light Temp Sender has 2 functions.
NTC Thermistor to run the gauge. Think ~ 1500Ω at "room temperature." Exact Ω depends on actual temperature at the tip.
Switch to turn on the "idiot light." This never close even in boiling water. Needed Oil heated > ~ 260°F to close to test.
Both are grounded to the metal shell.

ECT for ECM has NTC Thermistor between pins and Isn't grounded to the shell.

See my Cave, Sensors Quick Ref

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

i KNOW, THAT WHAT THE MANUAL SAID, but i GET NO RESISTANCE FROM ETHER PRONG
HOW COULD 4 SENDING BE BAD?????

The Fiero uses several different temperature sensors. The one with the Yellow and Black wires is a temperature sensor for the computer. The connector looks like the one in this picture. And on that sensor, you will get resistance pin to pin. And you will have an open pin to ground.

The other is for the temp gauge/temp light. Key on - engine off - it will have a Dark Green wire that when grounded will illuminate the TEMP light and a Dark Green/Yellow that when grounded will cause the temp gauge to peg high. It has the funky rectangular plug. Each wire is a separate function.

WOW, that is the answer I was looking for. every thing shows the ecm as the one going to the gauge on the left rear of motor.
where is the other one at???
the manual just shows the ecm and the temp for the fan

thanks, thanks
lost a lot of sleep over it
MIKE

The one for the gauge is by the coil on the V6.

https://www.fierostore.com/Tech/Default.aspx?Id=99

If a parts store tries to sell you a sender for the gauge that doesn't have the same connector as the old one, it's not a sender for the gauge.


The pin next to the notch is for the light and normally the Dark Green wire connects to it.

The pin away from the notch is for the gauge and normally the Dark Green/Yellow wire goes to it.

The shell of the connector normally has baked away and fallen off. The wires many times get reversed causing the temp gauge not to work and the temp light to light dimly when the engine gets up to temperature. Reversing them back fixes the problem.

A new shell can be purchased for cheap here - http://rodneydickman.com/pr...1acf0bc46a6a00b19c5c - It snaps over the existing metal terminals and you are back in business. Put some dielectric in the connector since GM stupidly used a connector that wasn't waterproof in this location.

WHAT happen the old wire plug in was broken and just the wires sticking out. so I ordered the sensor and plug got it and it is the one for the computer. i got the right one and work

THANK EVERYONE
MIKE