Shorkyz

Well i recently bought a 1986 Mada RX-7 GXL. Since I've had it its been having cooling problems, i figured out the main problem is because the fan clutch is faulty. I ordered a new fan clutch, a genuine mazda thermostat, and a greddy 19psi rad cap (stock = 13psi). I have also replaced the water pump. Pretty much all of the mechanical cooling related parts will be new, but i found something interesting while i have a few parts off.

What are these wires for??

As you can see there is what looks like to be a coolant temperature sensor at the bottom left hand side of the radiator with two wires coming out of it which lead to nothing, one is orange and the other is solid black.
At the top of the radiator there is another wire that leads to no where which is also orange with a black stripe
There is also 3 wires coming out of the wiring harness all orange with a black stripe. 2 of these wires lead to no where but one is connected to the body as a ground.


If anyone could help me out with these wires i would greatly appreciate it. My biggest question is if they are stock or if they were put on by a previous owner.

Thanks, Jacob.

Landon303

iTrader: (25)

well the 2 at the bottom of the radiator are for a temp switch. It will close a circuit when above a certain temperature (60*F I believe) and tell the engine that it's warm enough to do the cold start 3k warm up rev (AWS I think it's called.). These wires need to be in place though, as with them disconnected (permanently open switch) the ECU won't ever go into closed loop operation, and then this becomes a fuel consumption issued.

In the second picture, I'm willing to be the wire leads to the coolant level sensor at the top of the radiator. It looks like they spliced it? And grounded it out on that OEM airbox mounting bracket. I bet if you undo that blue wire you'll get a low coolant warning light/buzzer assuming that's all still hooked up.

HAILERS2

The two wires at the bottom of the radiators left side were on a STK radiators water temp sensor. This sensor detected water over???? I forget...60*F and when that temp was reached there was then a connection b/t the black gnd wire and the brown wire and that signal was sent to the ECU. It effected the relief solenoid which in turn effects the amount of air from the airpump to the ACV blah, blah, blah. I believe it also effected the air bypass valve/BAC in someway as long as the water was under 60*F. I forget right now.

IF you just couple these two wires together that'll be just fine, since you don't have the water temp sensor anymore. No harm will come doing this. See page 4A-35 of the online manual. It's emissions related on the whole and was only made a difference if the water in the radiator was colder than??/ whatever the manual says that temp was. See page 4A-46 of the FSM.

The wires at the top of the radiator. There is a water low level sensor in the top of the radiator that has one wire coming from it. That wire connects to a pure brown wire on the right area of the radiator. See page 50-40 of the FSM wiring manual. This sensor detects a low water level in the radiator and when it does a buzzer comes on constantly til more water is put in the radiator. As long as there is a GROUND on the brown wire there will be no detection of a low water situation therefore no constant buzzer going off.

Seems on your car someone has permantley grounded the pure brown wire so the low water buzzer won't go off. Why? I have several guesses and don't care to speculate right now.

Shorkyz

So to my understanding i need to figure out where the 2 wires at the bottom lead to and re-connect them so the engine runs in closed loop. Do you know where the 2 wires are supposed to be connected too? I do not have a manual or a wiring diagram so i have no idea where they go to.

Shorkyz

I believe it was grounded because who ever owned it before me never replace the fan clutch so it was constantly loosing coolant which would cause the buzzer to go off. I am trying to make this car run as best as possible to factory standards so i will be trying to re-connect the coolant level sensor. Thank you for informing me what the top wire is for.

Landon303

iTrader: (25)

Here ya go:

http://www.rotaryheads.com/PDF/2nd_gen/

The WHOLE 2nd gen FSM. The wires from the rad temp switch should have a male & female end, and color coordinated wires w/ the wires they connect to. And in all actuality, if it's a switch, it shouldn't matter which connects to which, as it's either open or close circuit lol

HAILERS2

The two wires at the bottom of the radiators left corner area...........the black wire is a ground. The Brown wire is part of the FRONT harness and terminates at pin .....1H of the ECU.

Like I say, just couple those two wires together and the system will act just like a stk 86 RX7 once the water temp gets up to 60*F. I've been running around with those two wires coupled together for yrs now on three RX7 with no after effects. I KNOW how that part of the system works and I KNOW that's all that is needed. IF you want to go pure stk..........go buy a radiator with the water temp switch bung on the bottom of it and buy a temp switch and connect the wires to it.. Counterproductive imho.

The brown wire for the low water level sensor on the right side of the radiator is also a part of the FRONT harness and its other end connects to the METER harness inside the car and from there goes to the combination meter.

EDIT: I see. You did not know that the stk radiator had a BUNG on the bottom left and in this BUNG was a water temp switch screwed into said BUNG and this temp switch had two pins the two wires you interested in, attached to them. I see now.

Wiring diagrams out of the MAZDA FSM are in the FAQ thread at the beginning of this site. Well, the LINK to the manuals is there in the FAQ.

The water temp switch at the bottom of the radiator is shown on one of the pages out of the FSM I mentioned in a earlier post. It's in the FUEL AND EMISSIONS section of the online FSM.

The water temp switch looks just like the depiction in the attached jpg below.

Shorkyz

I'll have to take a look at it. My parts will be here sometime towards the end of the week so i hope i can solve my problems. Thanks guys!