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91 Camry fan and temp gauge issue

  #1  
Old 12-04-2013, 05:01 PM
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Default 91 Camry fan and temp gauge issue

Hello after countless searching with no luck I decided to ask here. I have a 91 camry with the 3sfe engine and AT. The temp gauge quit working and at the same time the fans stopped working. I think its the Coolant temp sensor (or the equivalent) But before I buy one I want to make sure that it is the most likely problem. Does anyone know for sure?
 
  #2  
Old 12-04-2013, 08:37 PM
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If the car has a working A/C system, the radiator fans will cycle on/off when the A/C compressor cycles on/off. Turn on the A/C with engine running and watch for fan operation in sync with compressor operation.

The fan temp switch and gauge sensors are located on engine coolant intake housing.

Sensor wire may be Yellow/Green, fan switch Brown/Red.

Remove the wire from the fan switch and the fans should start if ign key on.

If both fans and temp gauge not working also check wiring.

Check ohm resistance of sensor.
Denso brand
Approx 226 ohm @ 122F
Approx 26.4  @ 239F

Yazaki brand
Approx 152.7 @ 140F
Approx 26.4 @ 239F
 
  #3  
Old 12-05-2013, 12:49 AM
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OK will try the A/C tomorrow and see. the only wiring issue this car has ever has is the starter circuit in the ignition switch quit about a year before this happened, had to use a jumper wire to start it since. I was driving home with it and noticed the gauge wasn't working, got home (3 miles) and the coolant was boiling in the radiator and the fans weren't on. decided to stop driving it. It has set for5 months. But now the minivan started knocking and now I gotta get the Camry going again.
 
  #4  
Old 12-05-2013, 02:28 PM
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The fans only operate when the coolant temp exceeds 199F. This happens if the car is stopped or in stop and go traffic when this is not enough air flow through the radiator.
 
  #5  
Old 12-13-2013, 04:46 PM
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Ok the snow finally melted and I got a battery and the fans do turn on when the a/c is on but not at all when its off, even when the engine reaches boil. The gauge doesn't work at all.
 
  #6  
Old 12-13-2013, 08:07 PM
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If the fans do not turn on when coolant is overheating the coolant temp switch may be bad. The switch is an on/off switch the opens when its temperature reaches 199F.

The switch may look like those at the link below:

1991 TOYOTA CAMRY Temperature Sender / Sensor

The switch has one wire perhaps Brown/red Red.

The gauge temp sensor may have a Yellow/Green wire. The sensors ohm resistance changes with temperature.

The switch and sensor should be located on the radiator coolant hose manifold at the water pump.

The fans should run if the electrical plug to the switch is unplugged and ign switch on. If not check cooling fan relay No 1.

The coolant fan switch should have no electrical continuity when coolant temps are over 199F. You can place the sensor in heated water on a stove.

In the future do not run the engine to boil or risk a blown head gasket. If needing to test the switch or sensor place them heated water on a stove and use a thermometer and an ohm meter.
 
  #7  
Old 12-14-2013, 12:34 AM
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Yeah I have had to change a head gasket on this already, actually a small handed friend did most of it since my hands are to big to reach some of the bolts. As soon as it started to reach boil I hit the a/c switch and it cooled off. It cools fine with the fans working and air temp at 27 degrees.
 
  #8  
Old 12-14-2013, 11:14 AM
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Great! Look into the coolant temp switch and relay.

The fan system has 3 relays to operate the A/C on and coolant temp systems. If fans work with A/C then suspect the coolant temp switch.

Cooling Fan Relay No 1 operates the fans in conjunction with temp switch. When the coolant reaches 199F +/- this coolant switch OPENS) to turn OFF this really and turn on another relay which turns on the fans.

When the A/C is on, the fans are connected electrically in series thus each fan receives a lower voltage and turns slower. When the coolant temp switch is open the fans are connected in parallel and receive full 12v and turn faster.

The problem is in the coolant temp switch and No 1 relay area.

The temp gauge sensor for the dash is a completely separate system. Make sure the the wires to the two sensors were not switched (if possible) or the wiring is damaged as is strange both temp gauge and radiator fan temp switch fan system do not work. But both are in the same area.
 
  #9  
Old 12-15-2013, 02:57 AM
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I though it strange too that they would both quit once I found out they were 2 different switches. I also just noticed that the o/d off light has stopped working as well. IDK for sure what else in the dash stopped working. but the Tach, Speedo, and gas gauge work still. Would it possibly be a fuse or something for the dash. Still sounds strange to me.
 
  #10  
Old 12-15-2013, 04:19 PM
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O/D light is powered by the Gauge fuse. This fuse also powers fuel gauge and tach, if these work the fuse is OK.

Also look around the upper radiator hose coolant exit manifold on the head for these temp sensors.

Have you checked for a wiring problem?
 

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