Coolant temp switch/sensors; What do?

[iansane]

Are the switches similar from the e to i? (aside from how many there are?). I was lead to this post on e30tech but are those the same for the e version? I've found seven senders/switches and I wanted to know what they all did.

Two on the radiator; Top is low speed aux fan switch and bottom is high speed aux fan switch. Not a huge deal here. If I yanked my mech fan would the aux be enough to cool the motor? What temps are these switches at?

There is a small coolant hose that exits the thermostat housing and heads back to the throttle body with a two pin (separate blade style terminals) sensor T'd inline. What is this for? In this picture the sender is located in hose #14.



I'm guessing at the rest of these so please correct me if I'm wrong.

#16 is this;

The thermo-time switch for cold start, correct? My cold start injector leaked like a sieve out onto the valve cover so I deleted it a few weeks ago with no ill-effects (so far!). I'm hoping I can just pull the sender and plug the housing there.

#15 is this;

and only bumps idle for cold rpm, correct?

#13 is this?

And controls the fueling from the ecm?

What is #12? Is that the cluster sender on my e model? Looks like just has a spade connector on it, not the fuel injector style connector like the later cars?

[Gregs///M]

The realoem.com page on this pretty much outlines every question you just asked. Typically the two prong sensors are for ECM management. The single prong are for temp gauge.

The sensors in the radiator are actually switches and switch at certain temps. That detailed info can be found at Realoem.com for your particular car or the car the parts came from. Most are interchangeable.

[iansane]

Yeah... except not. RealOEM answered one question. If they were the same. I should've just looked up both cars and the part numbers. Maybe I'm missing something but can anything else be gleaned from there? Every descriptor is just "coolant temp sensor". Nothing about what the sensors correspond to? It looks like the only one that is the same between the E and I is the two pin fueling control for the ECM. I was hoping for confirmation on what the other sensors did and maybe what the lone sensor in the TB hose was for?

[Gregs///M]

Yeah... except not. RealOEM answered one question. If they were the same I should've just looked up both cars and the part numbers Maybe I'm missing something but can anything else be gleaned from there? Every descriptor is just "coolant temp sensor". Nothing about what the sensors correspond to? It looks like the only one that is the same between the E and I is the two pin fueling control for the ECM. I was hoping for confirmation on what the other sensors did and maybe what the lone sensor in the TB hose was for?

Sorry about that. Thought the realoem would list that info, actually sometimes they do, but sometimes they do not.

Try reading their resistance at room temperature. If the resistance is the same, they can be interchanged as long as their connector is the same. I know the temp gauge uses a 1k thermister (thermal resistor) but not 100% sure on the others. ECM sensor might use a 10K, which is very common on other cars however I have not confirmed that.

You might find clues on the switches themselves, as to which temp they switch at. Most likely a Celsius rating.

The ETM might have some info in their respective sections but I do not recall any figures relating to your question.