2000 Toyota Camry It blows 4 amp starter fuse when key is turned

Tiny
CAMRY OWNER 2000
  • 2000 TOYOTA CAMRY

Electrical problem
2000 Toyota Camry 4 cyl Front Wheel Drive Automatic

If you start car by jumping starter, it blows the 10amp gauge fuse after a few minutes of run time. I have replaced the PCM, the neutral safety switch, and pulled the relay to the fuel pump. It still blows the 4amp starter fuse when ignition is in start position after all of that. The engine was recently rebuilt and all connectors are in their receptacles, and all grounds are hooked up. I idled the car for 5 hours with no problem, and drove it for 30 miles before this happened after the motor was rebuilt. The only problem that I was concerned with before this happened was that the temperature would have to get in the red before the cooling fans would come on. And the ac didnt work even though it did before the rebuild.

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Saturday, May 8th, 2010 AT 6:28 PM

18 Replies

Tiny
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Hi Camry Owner 2000,

For the temperature to reach HOT before the fan starts working indicates a possible fault with the fan switch.

The fuses blowing indicates a shorting and it could be bare wires that is touching somewhere causing the shorting.

Such faults would not be easy to diagnose.

You mentioned 2 fuses blowing? Do they blow when something is operated?

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Sunday, May 16th, 2010 AT 12:38 PM
Tiny
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Yes if I unplug the starter and jump it from the battery I can actually get the car to run. But soon it will either blow the 10amp dashboard(guage) fuse or a 14amp fuse that goes to something that controls the dash power also. But if I just leave the car ignition in the on position but not run the engine none of the fuses blow. By the way can a PCM be tested out of the car? If not can a PCM blow fuses? I also have unplugged the two temperature sensors and it still blew the 4amp fuse on start-up. I also understand that the ac is supposed to turn a cooling fan on low when switched on and both fans on low when operating temp. Is reached. Where is the fan switch?

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Wednesday, May 19th, 2010 AT 12:16 AM
Tiny
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The circuit runs through the neutral safety switch on the transmission, can you check the wiring harness there to see if you have pinched the wires installing the engine?

The fan switch ( water temperature switch ) is located at right front of engine.

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Wednesday, May 19th, 2010 AT 10:59 AM
Tiny
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It is the 5amp starter fuse and the 30 amp power fuse (for medium current) apologies for misinformation.

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Thursday, May 20th, 2010 AT 2:20 AM
Tiny
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Here are the components that are powered by the respective fuses. Any fault with the respective compents would cause the fuse tp blow and it is not going to be easy to diagnose.

If running the engine without shifting into any gears and the fuse blows, the two items that would cause the fuse to blow would be the Engine PCM or combination meters.

Starter fuse 5 A =
Combination meter
Electronically Controlled Transmission an A/T indicator
Engine Control
Starting and ignition

Power ( 30 A) =
Moon roof
Power seat
Power Windows

Does the Powe fuse blows everytime the engine is running?

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Thursday, May 20th, 2010 AT 10:39 AM
Tiny
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No the fuse didn't blow when I just drove it a couple miles today, but a few days ago the 10amp gauge fuse blew when I drove it a few feet off the ramps it was on. I have purchased another ECM (PCM) and am convinced that the problem is not with that. I thought the short was around the shifter and took that area apart as well, but no melted or bare wire. Is there a likely area the short could be in or is it anywhere in the car is game? Wouldn't it have to be something pretty major to blow the power fuse? Could the problem be linked with the low temp switch and ac issue? Where is the fan switch located, is it just the low temp sensor? Does all of this point to a loose wire causing all of this, or could it still be a replaceable component?

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Thursday, June 17th, 2010 AT 7:44 PM
Tiny
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The starter fuse is related to the shifter and you could be correct about the problem being near the shifter.

You mentioned the gauge fuse blowing, so this is not the starter fuse?

The power fuse could be a separate issue and it is conincidence that it is blowing the fuse. It definitely is a short somewhere and you can test it by operating the different components to test if any is not working correctly before the fuse blows.

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Friday, June 18th, 2010 AT 8:35 AM
Tiny
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No it is not the starter fuse, that is 5amp and blows consistently when ignition is in the start position. I do have something to report of interest. I unhooked the neutral safety switch and tried to get the 10 amp gauge fuse to blow(its on the diagram you showed me) but it didnt, that is also when I drove the car to auto zone. Then I hooked up the neutral safety switch and it blew the 10 amp gauge fuse. But I have already replaced the switch with another one from the junk yard so I am thinking it is in the wires them selves. Also can you tell me what to do to fix the cooling fans to come on at operating temp because my car has to heat up to red line before they come on and I just dont think it is good for a new engine to goto redline over and over.

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Monday, June 21st, 2010 AT 5:39 PM
Tiny
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The shorting of the gauge fuse seems to be from the starter circuit.

Unplug the starter relay and test if the fuse blows.

For the overheating, if unplugging the fan switch connector turns on the fan, then either there is insufficient coolant iin system or the fan switch is faulty. If coolant level is correct at radiator, replace the fan switch.

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Tuesday, June 22nd, 2010 AT 8:40 AM
Tiny
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Can you tell me where the fan switch is? If I unplug the temperature sensor nothing happens to the fans. So I assume there is another thing you are talking about. On the subject of blowing the fuse, to blow the gauge fuse the vehicle must be running and apparently moving, I dont know exactly what has to be executed to make it blow. All I have noticed is that when the neutral safety switch is unplugged it apparently doesn't blow, even though the starter fuse will. I hope this helps.

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Tuesday, June 22nd, 2010 AT 10:57 PM
Tiny
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The fan switch is located at rear bottom of radiator. If unplugging the switch does not turn on the fans, bridge the terminals with a jumper to check if it does.

The starter fuse blowing indicates a short between the fuse, Neutra (PNP) switch and the starter relay.

Unplug the starter relay and PNP. At PNP wire connector, test for continuity between terminal # 6 and body ground. If continuity is present, the wire is shorted to body. Check for bruised wirings.

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Wednesday, June 23rd, 2010 AT 9:38 AM
Tiny
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I replaced the one you spoke of and the fans still wont come on until red line. I believe that that one is the high temp switch. (As when I unplugged it the fans come on full blast not on low) The fans dont come on when when I unplug the low temp switch. Does that signify a short in that line, maybe? Also I did as you asked on the neutral safety switch no. 6 and a ground. I got continuity but only in an increment of full. Does that go directly to the starter fuse or starter relay, or does it go through the ecm first? I really appreciate your help, I feel we are going to find the solution soon.

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Wednesday, June 23rd, 2010 AT 7:33 PM
Tiny
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I have checked lessened continuity when hot and it is good, so the low temp switch is not the problem. I checked voltage through the wires and it would only register just above zero. By the way when I first checked it, it was going up and down with I think spark from the engine. Is it possible for the spark plug wires or the coil pack to feed back through the low temp wires and blow the computer? After I moved the wires away from the coil pack it stopped surging. (It will shock you pretty bad when the engine is running) So what does it mean if no power is coming to the low temp switch? Is that the wire I need to track and see if there is a spot thats bad? Or could the computer be bad and causing all of the problems?(Because of feedback from coil) Because I have replaced the computer twice already so I was convinced it was not the problem. (But I was afraid of blowing the computer over and over because of another problem that needed addressing.)

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Wednesday, June 23rd, 2010 AT 9:10 PM
Tiny
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Seems the coil pack is leaking and that is interfering with the wires passing nearby. You would have to check if the coil pack, soark plug wires or spark plugs are loose, or bad causing the spark leakage.

Problem should not be caused by the PCM but rather the spark plug wires and stray sparks.

If no battery voltage is present at the low temp switch, it means there could be a break in the wire and movements would cause intermittent failure. Yes, you need to trace the wire to check for possible breakages or bared wires causing the fuses blowing.

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Thursday, June 24th, 2010 AT 10:23 AM
Tiny
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I tested the low temp switch again and it is sending 5-6 volts, but I think it should be 12. Also if I unplug the low temp switch I think the fan should come on low but it doesn't. Any ideas like a resistor or something, I can't figure it out.

BTW I looked and found I did pinch the harness so I redid the wiring and now the problem is fixed for the blown of the fuse problem.

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Wednesday, June 30th, 2010 AT 10:54 PM
Tiny
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The fan is not a two speed fan and if they come on only when the gauge reading is high, possible causes are :

1. Temperature switch bad or wrong spec.

2. Gauge not accurate. When the gauge reading is high, does the coolant boil out to the recovery tank? Does the fans stop after running for a while?

3. Clogged radiator.

You mentioned the low speed switch, where is it located?

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Thursday, July 1st, 2010 AT 12:30 PM
Tiny
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In response to not having two speed fan, I figured its voltage gets sent through a resistor, like the fan inside the car. That is how the fan could have a high and a low. Coolant does not boil out when the temp is high, but the fans come on probably just before that happens. Once the temp goes down the fans shut off till it gets hot again. Radiator flows well, no detectable clogs. The low temp switch is located right next to the temperature sensor on the tube exiting the engine or return flow to the radiator. (Not the water cock where the thermostat is located.) I have tested the resistance on the low temp switch. When cold no resistance, once operating temp is reached according to the temp gauge, there is resistance to the flow of electricity. I really think that there has to be a resistor in line that is bad, but I dont know how to find its location.

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Friday, July 2nd, 2010 AT 11:54 AM
Tiny
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There are no resistors in the circuits but it consists of a few relays. I have emailed the schematics to you.

Since the coolant is not boiling over due to the high temperature reading, there is a possibility the temperatutre is correct but the reading is inaccurate, possibly due to a faulty gauge or sending unit.

Get a temperature gun to test the temperature of the coolant when the reading is high.

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Friday, July 2nd, 2010 AT 12:51 PM

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