Temperature Sensor Issues ( Temp gauge not responding)

[RJ_Ranger_Man]

So I recently changed out my temperature sensor out and now my temp gauge isn't responding and it was with the old sensor, I can't figure out what' I Did Wrong, so if anyone has a clue could you let me know??? ahh' ight then ...

 

[RonD]

Fuel injected engines have 2 temp units
ECT sensor, 5volt, 2 wire, only used by the engine computer

Temp sender, 12volt, usually 1 wire, can be 2, only used by dash board temp gauge

They look similar but are not at all the same
Most parts stores will send you away with an ECT sensor, lol
You often have to spell it for them, S E N D E R, sender

1997 should still be 1 wire, a red/white wire
NEVER put tape on the threads of these, they need a good metal to metal ground to engine

To test the wire and gauge use a jumper wire from battery negative(ground) to the unhooked red/white wire
Turn on the key
Temp gauge should go all the way up to HOT
If so then wire and gauge are OK, replace sender
If not then wire or gauge has the problem


Just FYI, ECT sensor has a grey/red and green/red wires, always 2 wires

 

[RJ_Ranger_Man]

I believe I have the right sensor here's some pics to show you what I changed but I'm gonna do your test now...

Results:
So what happens if it only goes to halfway between hot and cold. here's some pics

 

[RonD]

Yes thats the correct sender, 1 red/white wire

Check the connector and wire for corrosion
1/2 way would indicate the red/white wire is not fully grounded by the jumper wire, or has extra resistance in the circuit to the gauge

Sender works like a light dimmer or volume control, resistance, direct ground should be 0 resistance so gauge would show full movement, so goes to HOT
1/2 way means there is still some resistance in the red/white wire or the gauge

 

[RJ_Ranger_Man]

Ok cool thank you so after I check the wire and find no corrosion, then what would be my next step ??? and if I do find corrosion just replace the wire right? I'm learning a lot thank you...

 

[RonD]

I would get a Volt/OHM meter, they are not expensive and will save you hundreds of dollars, $15-$30, it needs a battery inside

With key on, test the Voltage(20vDC setting) on the red/white wire while its unplugged, so put red meter probe on red wire and black meter probe on engine metal or battery negative(ground)
Should see 9-11v

Switch meter to OHMs, 200ohms if it has that setting
Put either color probe on Senders connector and the other probe on sender metal "nut" area, its ground
If engine is cold it should show about 74ohms +/- 5ohms, sender is OK

 

[RJ_Ranger_Man]

Ok so I figured out it's the pigtail so I ordered the replacement from Amazon because it was cheaper (big mistake) but now I gotta work with what I got until I get the right part, but is there any way I can make the part I need with what parts I do have I think I have an idea but would like some input or maybe a warning not to ,any ideas would help pls and thank you.

 

[RonD]

Just cut away the exterior of the connector until it can slid into the sender and make contact with pins

One pin on sender is the Ground side, so connector can be reversed, ground side has the black wire, you can test which pin with ohm meter
Will show 0 ohms to engine ground

 

[RJ_Ranger_Man]

Ok thank you I got it to fit but still nothing from my gauge it still has no response so back to the drawing board im think its the gauge it self at this point ill post back woth more info as I get it.

 

[RonD]

So what happened when you grounded the Red/White stripe wire and turned the key on?

I thought you said Temp gauge went up

 

[RJ_Ranger_Man]

So what happened when you grounded the Red/White stripe wire and turned the key on?

I thought you said Temp gauge went up

It did but only went half way and it still isn't working its really getting on my nerves I'm running out of ideas,again...

 

[Burnsy]

It did but only went half way and it still isn't working its really getting on my nerves I'm running out of ideas,again...

Take it to a shop, or the dealership, let them worry about it, sometimes that's best, tell them to call you when its finished

 

[RJ_Ranger_Man]

Not really an option for me but I'm still trying to figure it out but might have to,if its still a issue.lets hope not

 

[Sdude2008]

Fuel injected engines have 2 temp units
ECT sensor, 5volt, 2 wire, only used by the engine computer

Temp sender, 12volt, usually 1 wire, can be 2, only used by dash board temp gauge

They look similar but are not at all the same
Most parts stores will send you away with an ECT sensor, lol
You often have to spell it for them, S E N D E R, sender

1997 should still be 1 wire, a red/white wire
NEVER put tape on the threads of these, they need a good metal to metal ground to engine

To test the wire and gauge use a jumper wire from battery negative(ground) to the unhooked red/white wire
Turn on the key
Temp gauge should go all the way up to HOT
If so then wire and gauge are OK, replace sender
If not then wire or gauge has the problem


Just FYI, ECT sensor has a grey/red and green/red wires, always 2 wires

First thank you for the great info you share. In this case you helped me know where to start on my non working temp gauge. Maybe you could suggest my next step. I have one red/white wire. The gauge pegged at hot upon testing/grounding. I replaced the sender with motorcraft and still no gauge reading. I’m thinking maybe somehow add a second wire. What do you think? Thank you.

 

[RonD]

Did you leave bare threads on the sender?
So it can ground to the metal intake/pipe

You can try a ground jumper wire from the sender's metal part(hex head part) to battery negative, do it after engine is already warmed up, see if the gauge responds, if so then that metal elbow does not have a good ground, maybe some one taped it up where it threads into the lower intake, so no metal to metal ground

In 1999 Rangers started to use 2 wire temp senders because intakes were starting to be made of plastic, so no reliable grounds
Same senders internally, and same threads, they just have a 2nd terminal on the top to hook up a ground wire
If the above ground jumper works and shows warm engine on gauge then you could install one of the new 2 wire senders, with a new 2 wire connector, splice in the red/white wire and add local ground

Or if the ground jumper works you could try grounding the Elbow the sender is screwed into
Looks like this: https://i.ytimg.com/vi/iaPINDb5m_E/hqdefault.jpg

When these rust out they leak and when replaced some people go nuts and use Teflon tape all over the threads, lol, this can prevent a good ground
You can use a hose clamp to add a ground wire on this elbow