2G Coolant temp sensor relay kit for fans. Can I use this spot?

[chrisman287]

When I bought my car the engine bay fuse box was relocated to the passenger side airbag spot and the aftermarket (look like eBay) fans were on a separate switch. I’m looking to drive the car more and don’t want to worry about monitoring coolant temp and turning the fans on and off myself.

I got better fans and this coolant temp sensor relay kit. I’m wondering if I can use this fitting on the thermostat housing rather than the supplied hose adapter?

If I can’t, should I cut the upper or lower hose to fit the adapter? I’m thinking lower.

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

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

 

[Anfurnyy]

When I bought my car the engine bay fuse box was relocated to the passenger side airbag spot and the aftermarket (look like eBay) fans were on a separate switch. I’m looking to drive the car more and don’t want to worry about monitoring coolant temp and turning the fans on and off myself.

I got better fans and this coolant temp sensor relay kit. I’m wondering if I can use this fitting on the thermostat housing rather than the supplied hose adapter?

If I can’t, should I cut the upper or lower hose to fit the adapter? I’m thinking lower.

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

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

Should be able to use the thermostat housing. I believe those are 3/8 npt threads. Are you wanting that temp sensor to activate the fans? If so you'll need a thermostatic switch like in the bottom radiator of a 1g to activate the relay.
I think that temp sensor you have now is only for sending temperature to a gauge?

You could always just find the wires for the OEM fans and wire the new fans into them with an updated fuse if the wiring isn't super obscure

 

[chrisman287]

Should be able to use the thermostat housing. I believe those are 3/8 npt threads. Are you wanting that temp sensor to activate the fans? If so you'll need a thermostatic switch like in the bottom radiator of a 1g to activate the relay.
I think that temp sensor you have now is only for sending temperature to a gauge?

You could always just find the wires for the OEM fans and wire the new fans into them with an updated fuse if the wiring isn't super obscure

Sorry, edited the second picture. There’s a plug with an allen whole in it. Was thinking to remove that and install the thermostatic switch that came with the kit.

 

[Anfurnyy]

Sorry, edited the second picture. There’s a plug with an allen whole in it. Was thinking to remove that and install the thermostatic switch that came with the kit.

IF that's a thermostatic switch then that should work. That single blade sensor doesn't look to be a thermostatic switch though. IIRC they are a 2 blade sensor that grounds when it hits a certain temp

 

[chrisman287]

IF that's a thermostatic switch then that should work. That single blade sensor doesn't look to be a thermostatic switch though. IIRC they are a 2 blade sensor that grounds when it hits a certain temp

According to the directions, the hose adapter is grounded to the relay harness. I’m thinking I can just ground to the thermostat housing itself

I’ll likely bench test the set up to see how it works. I got a 200° switch that’ll bring temps down to 180°

 

[DSMPT]

When I bought my car the engine bay fuse box was relocated to the passenger side airbag spot and the aftermarket (look like eBay) fans were on a separate switch. I’m looking to drive the car more and don’t want to worry about monitoring coolant temp and turning the fans on and off myself.

I got better fans and this coolant temp sensor relay kit. I’m wondering if I can use this fitting on the thermostat housing rather than the supplied hose adapter?

If I can’t, should I cut the upper or lower hose to fit the adapter? I’m thinking lower.

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

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

Yes you can use it on the thermostat housing but if the thermo switch is 1/8npt, it would require an 3/8bspt to 1/8npt adapter or making a 1/8npt port.

But you have ECMLink. I am wondering if you have a specific reason not to use it. Are the EGR or FPR solenoid activation both occupied? If one of them is still available, you can make it worked without adding a thermo switch and modifying the T-stat housing or radiator hose. Just use the relay w/ fuse holder and wires in the kit. In this way, it would allow you to control it much more flexible than just with a thermo switch.

 

[chrisman287]

Yes you can use it on the thermostat housing but if the thermo switch is 1/8npt, it would require an 3/8bspt to 1/8npt adapter or making a 1/8npt port.

But you have ECMLink. I am wondering if you have a specific reason not to use it. Are the EGR or FPR solenoid activation both occupied? If one of them is still available, you can make it worked without adding a thermo switch and modifying the T-stat housing or radiator hose. Just use the relay w/ fuse holder and wires in the kit. In this way, it would allow you to control it much more flexible than just with a thermo switch.

The switch is 1/8 npt so I’ll need the adapter. Thank you for that

Not sure where my EGR or FPR wires are.. all of those pigtails were removed when I was cleaning up the harness. ECMLink will allow me to activate the fans at a certain coolant temp through those sources??

 

[DSMPT]

Not sure where my EGR or FPR wires are.. all of those pigtails were removed when I was cleaning up the harness.

If you can't find it, you can trace or run a wire from ECU.

ECMLink will allow me to activate the fans at a certain coolant temp through those sources??

Yes, you can set the parameters as you desire and when all the conditions meet the parameters you set, ECMLink will trigger the fan relay. Just don't connect a fan ground wire directly to ECU pin. It will burn the ECU.

Like this.

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

 

[jdxnc]

The 2g ECU should be controlling the fans by itself, no need for any relay kit or sensors. It uses the main coolant temp sensor to activate the corresponding relay. Just let it do it's thing or as an output like DSMPT just posted.

 

[Anfurnyy]

The 2g ECU should be controlling the fans by itself, no need for any relay kit or sensors. It uses the main coolant temp sensor to activate the corresponding relay. Just let it do it's thing or as an output like DSMPT just posted.

It sounds like he's missing some wiring or don't know where it's physically located after a fuse box relocation

 

[DSMPT]

I assumed that the factory circuit has been hacked by the previous owner, that could be the reason why he wanted to make an independent circuit for the radiator fan rather than repairing the factory one since he already has the relay kit. I could be wrong about the situation though.

 

[chrisman287]

The 2g ECU should be controlling the fans by itself, no need for any relay kit or sensors. It uses the main coolant temp sensor to activate the corresponding relay. Just let it do it's thing or as an output like DSMPT just posted.

It sounds like he's missing some wiring or don't know where it's physically located after a fuse box relocation

I assumed that the factory circuit has been hacked by the previous owner, that could be the reason why he wanted to make an independent circuit for the radiator fan rather than repairing the factory one since he already has the relay kit. I could be wrong about the situation though.

@jdxnc these two are correct. I really don’t know where the fan wiring is and don’t want to open a can of worms looking for it Engine bay fuse box is in the passenger side airbag spot and all the wiring is there in the right kick panel. I have messed with it before just redoing all of the crimps/solders to prevent the possibility of future issues but it’s a mess.

I might try to track down the EGR or FPR wiring and do it that way. Will update with whatever I end up doing

 

[1990TSIAWDTALON]

That sensor will, more than likely, have SAE threads. The sensors on our cars are all BSPT. Don't try to thread it into the thermostat housing location, it will tear up the threads.

 

[jdxnc]

@jdxnc these two are correct. I really don’t know where the fan wiring is and don’t want to open a can of worms looking for it Engine bay fuse box is in the passenger side airbag spot and all the wiring is there in the right kick panel. I have messed with it before just redoing all of the crimps/solders to prevent the possibility of future issues but it’s a mess.

I might try to track down the EGR or FPR wiring and do it that way. Will update with whatever I end up doing

The relay for the fans is in the fuse box, you can look at the diagram and find the output on the underside of the board, just as easy as finding the FPS or EGR wiring.

Alternatively you could use the fan output direct from the ECU (pin 20) to a universal relay via ground and bypass the whole stock wiring situation.

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

 

[steve]

Last time I looked at DSMLink/ECMLink I was surprised to find that while you could set an offset for the ECU control of the fans there wasn't something like the EGR control over them directly. Did that change or did I miss it?

 

[chrisman287]

Alternatively you could use the fan output direct from the ECU (pin 20) to a universal relay via ground and bypass the whole stock wiring situation.

Would this be the correct way to wire it?

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

 

[Anfurnyy]

Would this be the correct way to wire it?

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

You wouldn't want the relay to have power all the time. Pin 86 should be connected to a switched 12v source that turns on with ignition.

 

[chrisman287]

Alternatively you could use the fan output direct from the ECU (pin 20) to a universal relay via ground and bypass the whole stock wiring situation.

I was finally getting around to doing this tomorrow but I think the only temp sensor in the housing that has a connector is the one that goes to the gauge cluster. I was going to repin the relay harness to go to the ECU.

I was looking at the instructions and might use the hose adapter but am wondering if I should use the upper or lower rad hose?

 

[Tyeler18]

I was finally getting around to doing this tomorrow but I think the only temp sensor in the housing that has a connector is the one that goes to the gauge cluster. I was going to repin the relay harness to go to the ECU.

I was looking at the instructions and might use the hose adapter but am wondering if I should use the upper or lower rad hose?

Your stock coolant temp sensor that runs to the ecu is what is used to control the fan output on the ecu. The single wire sender is only for the gauge on the dash, the 2 wire sensor is for the ecu and will give you live, accurate coolant temp readings at the ecu which you can then use to control the relay via the ecu like factory which is far better control than those china senders you install in line. I used basically that same kit on my 4g mighty max and 4g summit when I initially swapped them and they work OK until they don't and you're stuck with no fans. The ecu control is a far more reliable setup.

 

[chrisman287]

Your stock coolant temp sensor that runs to the ecu is what is used to control the fan output on the ecu. The 2 wire sensor is for the ecu and will give you live, accurate coolant temp readings at the ecu which you can then use to control the relay via the ecu like factory which is far better control than those china senders you install in line.

I took a peek quickly and do see the 2 wire sensor. I’ll give this a try tomorrow. If it doesn’t work I can just cut the negative wire that I’m running to the ECU and put it on a switch to ground that I’ll manually control instead.

 

[chrisman287]

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

So I wired it up according to this diagram but have pin 86 going to ignition source and 85 to pin 20 on the ECU and my fans did not come on 30 is going to the battery and 87 is going to positive of fans while negatives are grounded to the chassis.

Would pin 21 be better? Or should I put these things back on a switch? I could set CEL to come on at 210° and that’ll let me know to get the fans going

 

[chrisman287]

I bypassed the relay just to check if the fans work and they do

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

I also checked for power on pins 86 and 30 and they’re good.

I guess my wiring is jacked and the ECU isn’t sending the ground signal?

Or did I do it incorrectly? I cut the wire going to pin 20 and connected the ground from the relay directly to it. Should I have tied it in instead? @jdxnc

Also if they do work off the fan high will they come on at 210° or 220°?

 

[Tyeler18]

Considering in stock settings high speed doesn't trigger until 221 you weren't going to see it come on the high setting until it hits that. If you aren't letting it get that high of temp it'll never come on

 

[chrisman287]

Considering in stock settings high speed doesn't trigger until 221 you weren't going to see it come on the high setting until it hits that. If you aren't letting it get that high of temp it'll never come on

I did let it get that high and they didn’t come on. I’ll check again or maybe I’ll wire them to the low speed instead? Or is that a bad idea?

221 seems late in the game for the fans to come on.

 

[Tyeler18]

I did let it get that high and they didn’t come on. I’ll check again or maybe I’ll wire them to the low speed instead? Or is that a bad idea?

221 seems late in the game for the fans to come on.

Wire them to the low speed, no sense in having them on the high speed when the low speed comes on sooner