Wiring issues

Flanman55 · January 7, 2019

I have purchased a used Supermach700 (2008), It runs great after a new choke cable but. The temp sensor on the thermostat house is unhooked and can not find where it plugs back in. The fan has been un hooked from the sensor in the rad and cant figure out how it goes back together properly. The fan was wired to a by pass switch and i just always leave it on but would like to work it properly. I assume the sensor went bad and not changed.

any help would be great.

thanks

kenfain · January 12, 2019

Welcome to the forum Flanman55!

Unfortunately I have nothing useful to add to your question. But I do have a lot of real world experience in inherited work arounds. I've encountered many jury rigged wiring situations. My guess would be that it's not as simple as a bad sensor. The reason being, that the jury rig that you've described, would've been harder than an actual fix. Not to mention that it would've had some cost, considering wire, and switch, and time etc. So my guess is there's another root problem. Possibly a problem that requires expensive parts. Or unobtainable parts.

So my suggestion would be to prepare for the worst here. If you're pleasantly surprised then great!

Bear in mind, that I'm neither a mechanic, nor an electrical system expert. Maybe someone will chime in who is. YouTube is a great resource for finding ways to test sensors and stuff. Harbor freight has cheap volt meters. If there's not a wire dangling, that has an empty plug attached. You'll have to chase those wires by color. I'd test the sensor, and if it tests good, then look for the plug, or the wire that used to have a plug attached. It'll be the same color as the one going to the gauge, and/or the fan. There's your starting point, get back to us on this. Good luck!

Flanman55 · January 12, 2019

Thanks for the response Ken.

I am not worried about the costs at all, it's just a matter of getting it right. If some has pictures of their wiring for either of these two sensors that would be awesome.

Thanks again

Dan B · January 14, 2019

I don't know how close your Supermach 800 is to the HiSun HS800 but when I did a search for your machine, it gave me this link:

https://www.manualslib.com/manual/1113756/Hisun-Hs800.html?page=172#manual

Starting with that page, and continuing further, you'll find that there are two thermostats. One for the engine that controls water flow to the radiator. It is usually located near the top most radiator hose coming from the engine.

There's another thermostat that controls the radiator fans. It measures water temperature in the radiator. It is attached to the radiator fins. I suspect that the former owner had problems with that temperature sensor and installed a switch to make the fans run full time.

If the above link idoesn't apply to your machine, the info I gave you applies to most, if not all electric fan cooling systems. Good luck.

Flanman55 · January 14, 2019

Yes it is similar but not the same. Thanks though. Just looking for engine compartment pictures of where the temp probe wiring plugs in and pictures of how the sensor in the rad is plugged in

Thanks again.

Travis · January 15, 2019

@Flanman55.

You might message @strike250, he knows quite a bit about HiSun.

strike250 · January 16, 2019

The water temp coolant sensor is located on the thermostat housing. It is a 2 wire connector that goes back to the ECU. On the fan motor side of life there is also a 2 wire connector, but in-line to that is also a coolant fan motor circuit breaker between the fan motor relay and the fan motor. There is also a fan motor fuse before the fan motor relay. So all these things will need to be inspected to ensure a proper working coolant system. As for the wires to the coolant temp sensor, there should be a 2 wire connector close by. As most electrical connectors tend to keep their natural flow. So, it should be somewhere close to the position of the coolant temp sensor. I am attaching a wiring diagram to the coolant electrical system, as well as the colors of the wires to the electrical connector. The wiring diagram is specifically for the 2008 700cc version you have. If you can't find the electrical connector, it might have been zip tied to the wiring harness somewhere nearby. Check for a 2 wire connector not being used with the same wire colors as stated.

Again, check the coolant fan motor fuse first, then inspect the coolant fan motor relay, then inspect the connector to the coolant fan motor itself. I would also test the coolant temp sensor for proper OHM (see diagram). If all of these things are working properly, then the coolant system will work as designed. The fan should only come on after about 205 degrees. If the fan is on the entire time, (such as a fan bypass switch) the engine will not warm up properly, and thus run rich during the warm up cycle. You could end up fouling spark plugs over time. I hope this helps, if you have any questions after looking at this, please let me know. Matt

Flanman55 · January 19, 2019

Strike you for this info. I will have a look tomorrow

Flanman55 · January 20, 2019

Well,

i was looking today and it’s only a one wire out of the probe temp sensor and the is nothing in the area that looks like it should be plugged into it. I am confused

also. My bypassed fan quit working Is this normal?

strike250 · January 20, 2019

It's a EFI version right? Or is it a carburator one. Your year should be an EFI with a two wire sensor. The single wire sensors versions had a single wire with a fairly large brass ring connector going to it

strike250 · January 22, 2019

Here is the wiring diagram for the single wire type. Along with a pic of the sensor in the cylinder head. The color of the single wire might be White with Blue tracer.