Tem. Meter / Gauge Unit testing.
New sender and STAT, 1991 Kick
Rule 1: It is not an instrument , it has no numbers, the above shows my Photoshop reading with a new sender.
It's only 2 purposes is to warn of too hot, and slow thermostats. (or a frigid engine or cab heater)
Get an IR pyro gun (they are cheap) to find the truth.
The circuit is simple: (just 3 parts, sender, wire , gauge, same as in 1920 cars.)
The ignition feeds 12vdc to the Gauge , the other side of the Temperature guage goes to the sender and the body of the sender is grounded.
Simple to a fault.
It uses lots of current and is way too sensative to bad resistive connections. (and is slow to react , 1 or 2 minutes to go stable or less)
Meter Test. (fast)
Pre checks (noob levels) we do not rip the dash apart until last, ok? Only when the meter is known bad.
Motor cold , meter at maximum? fail 1
Unplug the 1 pin Gage sender near thermostat housing.
Did the meter drop to zero. Yes? then is a bad sender. (buy a new sender) if the meter stayed high, the meter is bad, or that wire, your touching, is grounded out.
Motor hot, meter at minimum? fail 2
Just put a lamp, at the sender pin and other lamp ot lead to ground (use clean metal on engine)
The lamp prevents damage to the expensive meter. (hard to find too) grin.
Did the meter go near full? yes, meter good, sender bad. No?, meter did not max out, then its a bad meter, replace meter (or the wire is cut ,end to end)
(oop's Suz dont sell meters now.....any more.)
FSM, all tests: (factory service manual)
If it varies?, then you have one of the problems stated in the last paragraphs below. Normal is about 40 ohms hot motor. 180║degree F, or up to 195║F.
The Test lamp:
Any GE/CM #1895 bayonet twist lock lamp
or a #194 car trim lamp works.
he latter lamp, is very common (as nails in USA) Remove a car fender trim lamp, ? and use that if no standard test lamp in you tool box.
Do not use tail lamps, they draw too much current. tail lamp number are 1156 and 1157.
Any lamp at about 1/4amp (0.25) is perfect. 12vdc. use the fender side lamps or any of the shelf ,AUTO STORE 12v passive TEST LAMP.
(3.4w lamp Jap. spec,means a USA GE #194) In Japan they don't use USA lamp numbers, only volts. watts and Lumen's
Do not ground out the Yell/white wire at the sender or the meter WILL be damaged. ( old school 1960 tactics, can wreck even a simple guage.)
The old Suzuki books tell you to ground it but all newer books show using a lamp test. (that is because if you leave it grounded, too long, the meter my get damaged , overheated!)
Why are we here?
If you are here because the gauge reads funny ( its not calibrated and has no scale at all , see ?)
If it deflects to any mid scale reading it is working.
If it moves up and down as you drive then consider the following issues before condeming this simple device.
Guage varies alot ,problem: (you =someone, anyone)
Or the STAT will float around and make coolant temperatures, vary like crazy. << A.K.A: the frigid Kick syndrome
Aka = also known as,......
When the thermostat is floating , the water (coolant) walks around the STAT, (illegal bypassing it) and this causes , cold coolant, and ECU that goes totally nuts.
The ECU just HATES this, and you EFI will suck fuel like NO TOMORROW !!!
The better condition the radiator is, the worse the Frigid.
Read the TSB and use the correct parts.
The Factory Thermostat comes with both gaskets, so is not a problem. SEE ? NOT A PROBLEM with TSB and FACTORY THERMSTAT KIT in hand.
The Stupid aftermaket , comes with the wrong gasket or none at alll, so buy both gaskets before doing the job. Splurge and blow extra $2?