Possible faulty ECT sensor/What can cause low heating?

[MikeV]

Okay so I just recently bought me a nice '95 Explorer XLT and I noticed the check engine light come on and I was planning to pull the codes at my school (im studying Automotive Tech) but after noticing some symptoms im wondering if I even have to (aside from erasing the code).

My heater isn't heating, well atleast not right. It heats but very little and I noticed the engine temp gauge is not moving at all and is staying at the bottom.

So i'm not sure but I think I read something about a bad ECT sensor could cause bad heating because it's not able to route the coolant into the heater core. But I could be way off, I have to go check.

But my real question is, how do you check the ECT? Can anyone who has a repair manual for this model explorer tell me what the resistance should be for the ECT? I think im going to take it off tomorrow and check the resistance and also check voltage to the sensor tomorrow.

Also, just in case this isn't the problem, anyone know what can cause low heating aside from the blend door not working properly?

 

[BrooklynBay]

Welcome to this forum! It sounds like you might have a bad thermostat which is stuck in the open position. I have the resistance chart in # 25 in my list of useful threads:

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[MikeV]

Ahh yea the thermostat! Thanks for the chart too, i'll check it tomorrow and give an update.

 

[MikeV]

It took forever but I finally got to pull the codes off my car and it did say ECT voltage out of range, but I was told it's because I didn't let the car warm up enough before doing the test, I also checked the resistance and it was about right. Though the resistance chart I found on shopkey5 was different from what you have posted. 68 F said it would be around 27,000 OHM and you have 37,000.

It was like 77 F when I did my test and I got 30 OHM's which is more or less close enough.

The 2nd code I pulled said my EGR signal was too low. According to the diagnostic procedure i'm supposed to test my DPFE sensor which took my a while to figure out what it was, but by the time I figured it out it was time to go. I'm gonna test it tomorrow at the shop and see what's what.

As for my heating I have yet to pull the thermostat out yet since Ive been trying to diagnose these other problems but I will soon and see what's up with that also.

 

[my98nnj]

Change the T-stat, your other problems will go away. The EGR may remain.

 

[96eb96]

Okay so I just recently bought me a nice '95 Explorer XLT and I noticed the check engine light come on and I was planning to pull the codes at my school (im studying Automotive Tech) but after noticing some symptoms im wondering if I even have to (aside from erasing the code).

My heater isn't heating, well atleast not right. It heats but very little and I noticed the engine temp gauge is not moving at all and is staying at the bottom.

So i'm not sure but I think I read something about a bad ECT sensor could cause bad heating because it's not able to route the coolant into the heater core. But I could be way off, I have to go check.

But my real question is, how do you check the ECT? Can anyone who has a repair manual for this model explorer tell me what the resistance should be for the ECT? I think im going to take it off tomorrow and check the resistance and also check voltage to the sensor tomorrow.

Also, just in case this isn't the problem, anyone know what can cause low heating aside from the blend door not working properly?

I had this same issue. First of all there are two "sensors." The one wire SENDER reports to the dash gauge. The two wire SENSOR is for the computer. On early OHV engines, the one wire sender AND thermostat are notoriously bad. Thermostats often fail open (no immediate risk to the engine but you have poor heat and maybe some drive ability issues)


You must replace BOTH to solve the problem. Optionally, after all these miles, it wouldn't hurt to replace the two wire temp sensor while you are in there...

BTW, the sender does nothing to divert coolant, only reports temperature.

I suggest a motorcraft factory T-stat that has a bleed hole.

 

[MikeV]

I did a full diagnosis today and my instructor helped so that he could teach us something in the process. I used the Solus and the Vantage Pro to do all the crap. I found out my DPFE Sensor (Differential Pressure Feedback EGR Sensor) is bad and that it needs to be replaced. This costs like $60 at autozone, but i'm going to call a place that sells parts for cheap to the school.

I'm gonna pick up a thermostat after my first class and then go straight to the shop to go swap it out. Hopefully this fixes it because it is getting way too cold for me in the mornings and I only live in GA so it's not as cold as other places.

 

[BrooklynBay]

Check the price on WWW.RockAuto.Com. There is a 5% coupon code on this site for them.

 

[MikeV]

I replaced the thermostat today and went ahead and fully drained and flushed my coolant system.

The car now heats fine (no more scraping ice after a good warm up) and my temperature gauge is actually reading the engines heat now, so the ECT is working properly.

All that's left to do is replace my DPFE sensor and I should be able to clear the DTC's from my truck without it coming back.

 

[BrooklynBay]

Did you put the regular or fail safe thermostat in?

 

[MikeV]

I put a failsafe