1G 3 temp sensors?

[MGushard]

hello,

I’m a super noob to this forum as well as to these cars. I good friend had a 91 Talon 2.0 no turbo base model in storage for 5 years. Aftermarket headers, new cylinder head and other various new parts. I don’t yet know what 1G or 2G means. He handed it off to me to get it running again and use it and possibly buy it from him since a one car family aint working so well for us. I replaced the fuel pump and got it running then was told it needed a new cooling fan switch before it could be driven since the fans wouldn’t turn on after reaching a certain temp. I have a Chilton repair manual that came with the car, have researched online to find the part that matched the one with the broken white plastic wire/plug housing that lives closest to the top of the engine near the thermostat. There are 3 of these sensors in this same area facing the front of the car, 2 more below the top one.

OK, what I need to know that the repair manual, YouTube and other online research and parts stores have not been able to tell me is, exactly what each one is called and what they do... I think I know the top one is the cooling fan switch. Have no idea what the 2 below that one are or what they do. The second one down had tape on the connector, (which is an odd white plastic thing with holes on the top facing up) no wires attached and no loose wires hanging anywhere to be found that might connect to it. The bottom one has a 2 prong connector with a black locking plug, one of the wires was broken and disconnected so I removed the plug and reattached the wires using those spade shaped crimp connectors, but I am unsure which color wire goes to which prong on the sensor or if it matters.

I’m having issues with the temperature going way up after idling for awhile (I’m guessing it probably needs a new thermostat since it’s been sitting in storage outside for 5 years) the fans turning on, and the middle sensor of the 3 not being connected to anything and am desperately in need of transportation ASAP. It seems like a very cool car and I can see why owners of these cars have formed groups, forums, clubs, etc. I can’t wait to drive it.. any help I can get to understand the 3 sensors etc. on the coolant/thermostat area would be greatly appreciated. Even a picture with labels would be a big help, I believe I could figure the rest out if I knew which one was called what and how to wire up the middle one and to what. It seems like my friend might have been driving it without the middle sensor even hooked up so I don’t know how important that one is to get it on the road and me to work and back until I can figure it out. DSMtuners kept showing up in my searches so here I am, most likely a soon to be Talon owner. Thanks!

 

[Mello]

Welcome aboard. First 1G & 2G are short for first generation & second generation. This stands for the model years body style. 1G are 90-94 & 2G are 95-99. There is 3G & 4G but these technically are not DSM's.
Anyway I'm a 2G owner so I don't have the specific answers for you. I recommend getting a factory "field Service Manaul" FSM because the Chilton's manuals are pretty poor. Go to this link => https://www.dsmtuners.com/threads/1...e-chassis-body-factory-service-manual.517383/
This link is one you should read through too. It's a good starting place for new DSM owners. https://www.dsmtuners.com/pages/resources/
Lastly, the members of this site are either knowledgleable mechanics are newbies that have used this forum & learned how to keep these cars running. Patiences is also benefical. Remember your 91 is pushing 28 years old & maintenance will be a priority. After your solve your cooling problem you should address all the regular maintenance & if you don't know if it's time for something particular do it & record the mileage so you can keep on top of the regular maintenance & intervals. You should probably plan a time belt maintenance/replcement as well. You do not want to have this jump or break.
Some 1G members will also jump in to help with your 1G questions. Best of luck.

 

[Dhan]

Well here's a reference to get you familiar with the thermostat housing and the sensors on it. Not sure if your thermostat housing is the stock one, but it should look similar to this if its a 1g car. You said the sensor that "lives closest to the top of the engine", which would be 6 in the photo which is the A/C switch. I think in your case though, you need to check number 5 in the photo.

There is also a sensor at the bottom of the radiator, underneath the passenger side fan. It's the thermosensor. You need to check to see if it is working.

The sensors might be okay though. Do you hear the relay click after the car gets hot enough, and then the fan doesn't turn on? Or does the relay click and then no fan turns on? Is the fan plugged in (dumb, I know, but it could happen) and is the wiring healthy?

The fan on the passenger side is the radiator fan, the fan on the driver's side is the A/C fan FYI.

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Photo made by 19Eclipse90

 

[MGushard]

Welcome aboard. First 1G & 2G are short for first generation & second generation. This stands for the model years body style. 1G are 90-94 & 2G are 95-99. There is 3G & 4G but these technically are not DSM's.
Anyway I'm a 2G owner so I don't have the specific answers for you. I recommend getting a factory "field Service Manaul" FSM because the Chilton's manuals are pretty poor. Go to this link => https://www.dsmtuners.com/threads/1...e-chassis-body-factory-service-manual.517383/
This link is one you should read through too. It's a good starting place for new DSM owners. https://www.dsmtuners.com/pages/resources/
Lastly, the members of this site are either knowledgleable mechanics are newbies that have used this forum & learned how to keep these cars running. Patiences is also benefical. Remember your 91 is pushing 28 years old & maintenance will be a priority. After your solve your cooling problem you should address all the regular maintenance & if you don't know if it's time for something particular do it & record the mileage so you can keep on top of the regular maintenance & intervals. You should probably plan a time belt maintenance/replcement as well. You do not want to have this jump or break.
Some 1G members will also jump in to help with your 1G questions. Best of luck.

Thanks a bunch! I will do some reading.. cooling problem solved sort of, it wasn’t overheating just the gauge acting up, fans are working too.

 

[MGushard]

Well here's a reference to get you familiar with the thermostat housing and the sensors on it. Not sure if your thermostat housing is the stock one, but it should look similar to this if its a 1g car. You said the sensor that "lives closest to the top of the engine", which would be 6 in the photo which is the A/C switch. I think in your case though, you need to check number 5 in the photo.

There is also a sensor at the bottom of the radiator, underneath the passenger side fan. It's the thermosensor. You need to check to see if it is working.

The sensors might be okay though. Do you hear the relay click after the car gets hot enough, and then the fan doesn't turn on? Or does the relay click and then no fan turns on? Is the fan plugged in (dumb, I know, but it could happen) and is the wiring healthy?

The fan on the passenger side is the radiator fan, the fan on the driver's side is the A/C fan FYI.

You must be logged in to view this image or video.

Photo made by 19Eclipse90

Thanks this is very helpful. Temp gauge was acting up so it wasn’t overheating, once I figured that out and saw the fan was working I took a little test drive down the road and back. The temp gauge would go between normal and almost all the way up, then randomly drop back to normal, but it never got too hot so I’m thinking #5 water temp sensor unit needs to be replaced. The wire to it wasn’t looking so good so changed the connector and rewired it. Then when I started it right after doing that it idled rough for half a minute then was fine. After it sat for a couple hours or so I started it again to go on a little longer test drive and get some air in the tires and it didn’t start so easily as before and idled rough again for longer until it warmed up. I read what causes this last night but now cant remember, I’m hoping that’s also the water temp sensor unit since it never did that until I fixed the wire on it. I didn’t check the Thermosensor yet, need to figure out how, will do that tomorrow when I replace #5 sensor.
Anyway, it’s super fast and fun to drive. Thanks again!

 

[MGushard]

Hello,
Can anyone recommend the best place to find parts? I ordered the cooling fan switch it’s called at the parts stores or water temperature switch it’s called on #6 in the diagram shared by Dhan. It didn’t fit. The threads didn’t seem to be tapered and we’re only half as long as they are on the one I took off. So when I tried to hand tighten it, the nut got too close to the thermostat housing and wouldn’t turn anymore. Plus the sensor part of it that is inside the housing wasn’t the same, had 3 stepped sections getting smaller instead of only 2 on the original, (not sure if this matters or not) I’ve been searching online to order one that matches exactly and they all show the one I ordered, and they all say it fits my vehicle, but it doesn’t fit. Thanks!

the first attached file I s the one I bought..

The second attached file is the one I took off and trying to replace

 

[MGushard]

I found the list of where to get parts, here in the resources section.