1998 sport a/c coolant temp switch

[gene.matthews]

Last fall I replaced the a/c coolant temp switch to fix the continuous running of the condenser fan and failure of the compressor clutch to engage. The fix worked great and gave more insight into the operation of the a/c. However the same symptoms have started again this summer. I assumed the coolant temperature switch, shown in documentation normally closed to ground, would show zero on the ohm meter measuring it out of the circuit. I grounded the lead from the A/C AMP to the coolant temperature switch and the system worked fine, so I replaced the switch again and reconnected the A/C AMP wire. The symptoms returned. I measured the old switch, DC ohms, at 120, and both of the new ones I bought at 700 ohms. None of these three will make the symptoms quit.

1. Are the switches supposed to read zero on an ohm meter?
2. Does the A/C AMP have a threshold for that lead?
3. Is there another possible issue that would cause these symptoms that I am overlooking?

I appreciate any help on this and I appologize if this issue is covered in another thread somewhere else in the forum, I search in earnest for it.

[fixkick]

the amp is a logic box, its purpose is to protect the compressor and to save engine from overheating.
defeating the AMP invites great risk.
but testing can be ok, of the Freon loop pressure are ok. are they, that would be first. no? yes,

the amp does many other things too, a long list, what is your ambient temperature out side, ?
so car drives ok? never overheats.
the A/C works ok?
my guess is you unplugged the overheat switch, and shorted the wires there and the fan turns off, right?


if yes for #3 , here are some more rules
YOUR overheat switch is bad, its normally closed, on a cold engine, closed means 0 ohms . (please do not tell me it worked with wrong switch, i dont want to hear that, the world is analog not digital)
the amp is not documented for input threshold, that means , how bad can a switch be and still work is UNKNOWN by anyone. near 0 ohm is good. 100 up is NO GOOD, 10 ohm ? who knows,
if hell bent to find the magic threshold use a 200 ohm pot there, turn the knob until the fan comes on, then remove pot, and read ohms, see the true threshold. (ohms)
and learn that it dont matter, the switch is a switch, not a resistor, its near 0ohms good, Id most meters can measure 0 very good, but will be less that 5ohm for sure.



you bought the wrong switch, this switch correct is a overheat switch, it opens at say 250f degrees. (there is only one correct part and 100s wrong,, )

if you went to say your local store in town, the clerks there would not known what a suzuki sidekick is , much less find this part, and sell you a generic useless ,temperature dash gage sensor. ( they sell parts wrong with great skill)

ill bet you 10 bucks you didnt buy that part from suzuki, but here in USA where is suzuki now, bugged out. chapter 11. here. 2 stores left? of 100s'
Are you in USA< you never said, so how can i direct you to proper parts, lacking this very very key fact.??

The ECU can tell the AMP to turn on, at anytime on that serial communications line (it does for , engine too hot, engine overloaded, throttle at wide open throttle)<< makes testing tricky no? but if you shorted the Overheat switch wires, that tells you the switch is bad.

but of you short the ac sensor and the fan goes off, then that sensor you bought is WRONG. (cold engine)
my answer is long, but i cant see your car, nor know if parts are missing, had engine swaps. or other things,? or that it really is J18 engine inside hood.
the correct sensor is for sure
suzuki
95573-60a50

suzuki lists it here.

https://www.suzukicarparts.com/parts/199...eid=214820


buy the correct sensor. it reads 0ohm in hand.


i looked for you and SMP top maker of sensors, does not make this sensor, the other 2, for engine yes, but not this 3rd AC only sensor. fact.

http://ecatalog.smpcorp.com/STD/#/vehicles

it's a thermal switch and not really a sensor, in the strict terms. (it opens or closed, only)

i looked at the G16 part and its same P/N
the 60a means that, means from early G16 design...



btw our ECT goes to 300 ohms at 180f (colder is x10 higher or more, on this wrong sensor)
and lower if hotter. so using this sensor is super bad idea if ever.
be CHAOS here. like that.

[fixkick]

some amps, btw,
have hidden sensor in the AMP casing.
this hidden amp sensor turns off AC if its too cold outdoors. (the fsm states that)
and may also turn on the condenser fan if its like 110F out doors, like in the Desert.
the newer the car the more true this is. (smarter cars, do that)
all modern cars run this fan, with the engine fan to boost air flows like stopped in traffic.
newer cars run the fans staged, as temps rise it adds more fans. to the ACT.
knowing all this makes diagnosing way more easy.\

j18 real

[gene.matthews]

the amp is a logic box, its purpose is to protect the compressor and to save engine from overheating.
defeating the AMP invites great risk.
but testing can be ok, of the Freon loop pressure are ok. are they, that would be first. no? yes,

the amp does many other things too, a long list, what is your ambient temperature out side, ?
so car drives ok? never overheats.
the A/C works ok?
my guess is you unplugged the overheat switch, and shorted the wires there and the fan turns off, right?


if yes for #3 , here are some more rules
YOUR overheat switch is bad, its normally closed, on a cold engine, closed means 0 ohms . (please do not tell me it worked with wrong switch, i dont want to hear that, the world is analog not digital)
the amp is not documented for input threshold, that means , how bad can a switch be and still work is UNKNOWN by anyone. near 0 ohm is good. 100 up is NO GOOD, 10 ohm ? who knows,
if hell bent to find the magic threshold use a 200 ohm pot there, turn the knob until the fan comes on, then remove pot, and read ohms, see the true threshold. (ohms)
and learn that it dont matter, the switch is a switch, not a resistor, its near 0ohms good, Id most meters can measure 0 very good, but will be less that 5ohm for sure.



you bought the wrong switch, this switch correct is a overheat switch, it opens at say 250f degrees. (there is only one correct part and 100s wrong,, )

if you went to say your local store in town, the clerks there would not known what a suzuki sidekick is , much less find this part, and sell you a generic useless ,temperature dash gage sensor. ( they sell parts wrong with great skill)

ill bet you 10 bucks you didnt buy that part from suzuki, but here in USA where is suzuki now, bugged out. chapter 11. here. 2 stores left? of 100s'
Are you in USA< you never said, so how can i direct you to proper parts, lacking this very very key fact.??

The ECU can tell the AMP to turn on, at anytime on that serial communications line (it does for , engine too hot, engine overloaded, throttle at wide open throttle)<< makes testing tricky no? but if you shorted the Overheat switch wires, that tells you the switch is bad.

but of you short the ac sensor and the fan goes off, then that sensor you bought is WRONG. (cold engine)
my answer is long, but i cant see your car, nor know if parts are missing, had engine swaps. or other things,? or that it really is J18 engine inside hood.
the correct sensor is for sure
suzuki
95573-60a50

suzuki lists it here.

https://www.suzukicarparts.com/parts/199...eid=214820


buy the correct sensor. it reads 0ohm in hand.


i looked for you and SMP top maker of sensors, does not make this sensor, the other 2, for engine yes, but not this 3rd AC only sensor. fact.

http://ecatalog.smpcorp.com/STD/#/vehicles

it's a thermal switch and not really a sensor, in the strict terms. (it opens or closed, only)

i looked at the G16 part and its same P/N
the 60a means that, means from early G16 design...



btw our ECT goes to 300 ohms at 180f (colder is x10 higher or more, on this wrong sensor)
and lower if hotter. so using this sensor is super bad idea if ever.
be CHAOS here. like that.

Thank you for the information and very quick too. I will order the genuine Suzuki part today. From your answer that seems like the place to start. The vehicle has always ran good and never overheated. The ambient temperatures where I live are 55 to 75F this time of year. I also appreciate the drawing and your insight. Thanks again.

[fixkick]

you're welcome and good luck.