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Post by silverdragon on Mar 7, 2013 7:23:28 GMT
Car related.
I have a 3 speed 4 position rotary switch on the dash that is the controller for the fan....
Its supposed to be [off-slow-medium-fast]
As of yesterday, its now anyone's guess as to what it will do.
From the looks of it, its a dash-out to get behind the switch.
Anyone got any clue what may have gone wrong, and if it something simple, like change a fuse, or is it still dash out (what looks like a a two hour job) JUST to change the fan controller switch....
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Post by privatepaddy on Mar 7, 2013 11:46:31 GMT
According to the Haynes manual for a RHD Toyota Camry/Vienta 1993-1996 there is a blower resistor unit attached to the Heater blower unit drivers side under the dash. It might be a place to start looking, but you have a later model so the position might be different.
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Post by silverdragon on Mar 7, 2013 12:40:15 GMT
Ahhh... I hear clicking from that at times, You may have something there.....
Thanks for that
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Post by privatepaddy on Mar 7, 2013 12:49:14 GMT
Ahhh... I hear clicking from that at times, You may have something there..... Thanks for that not a problem, cost you an ale later this year ;D |
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Post by GTCGreg on Mar 7, 2013 13:41:44 GMT
The switch usually feeds power directly to the blower motor through resistors for low and medium speed. For high-speed operation, the switch turns on a relay and the relay provides full power to the blower motor. That relay is often an intrical part of the speed control resistor module.
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Post by c64 on Mar 7, 2013 14:13:48 GMT
The classic design is 3 wires running to the fan motor which has a resistor array in its air path.
What can go wrong is that the resistors have burned out. Then the fan will only work on its highest setting (no series resistors).
Another common problem are the contacts them self. If they turn bad, the fan runs slower, sometimes more, sometimes less. The plastic around the contacts become fried and you need to replace the entire switch or you risk a fire!
And then there is the fan motor itself. Mine stopped working because the clamps of the coals became stuck in the rotor and the motor then had fried the resistors.
In modern cars, there's either a potentiometer or individual resistors connected to a real switch. This is a voltage divider setting the speed of the fan electronics which uses PWM.
If you have a bad switch and don't want to pop out the entire dash to fix it, you can modernize the old system. Spray the contacts and connect one of the wires to the imput of the switch to have full power on it. Use this to supply a BTS629A PWM regulator. Use the example in the data sheet but connect a 150Ω resistor instead of the "bulb" (between output and ground) and then connect the output to a BUZ11 Transistor which operates the fan. Use the rest of the wires to the switch for the "potentiometer" input and add resistors to the switch itself. Voilá, an electronic controlled fan running on the original (bad) switch! You might even want to attach a potentiometer to the switch and disable the steps.
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Post by c64 on Mar 7, 2013 14:14:56 GMT
The switch usually feeds power directly to the blower motor through resistors for low and medium speed. For high-speed operation, the switch turns on a relay and the relay provides full power to the blower motor. That relay is often an intrical part of the speed control resistor module. In most cases, there is no relay, the highest setting is directly connected to the fan motor. |
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Post by GTCGreg on Mar 7, 2013 14:22:06 GMT
The switch usually feeds power directly to the blower motor through resistors for low and medium speed. For high-speed operation, the switch turns on a relay and the relay provides full power to the blower motor. That relay is often an intrical part of the speed control resistor module. In most cases, there is no relay, the highest setting is directly connected to the fan motor. Maybe not on German cars but on US cars, almost all had relays for high speed. Not sure on Japanese vehicles. |
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Post by the light works on Mar 7, 2013 15:01:39 GMT
Chevys also have a circuit board between the switch and the blower - and not a dash-out job because my mechanic did mine cheap, and our car wash employee did my wife's cheaper.
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Post by c64 on Mar 7, 2013 15:06:34 GMT
In most cases, there is no relay, the highest setting is directly connected to the fan motor. Maybe not on German cars but on US cars, almost all had relays for high speed. Not sure on Japanese vehicles. German, UK, French, Italian, Czech and Japanese, maybe more but I hadn't worked on other vehicles. |
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Post by c64 on Mar 7, 2013 15:12:29 GMT
Chevys also have a circuit board between the switch and the blower - and not a dash-out job because my mechanic did mine cheap, and our car wash employee did my wife's cheaper. Depends on the car. Until the 80s, everything was highly maintenance friendly. The 90s were real tricky since classic wiring but everything covered up for aesthetic reasons. Then came the CAN bus which made things easier again. Just replace the ECU since it's almost every time a broken ECU which makes things fail. I drive a Passat of the 35i series. You can change the cylinder head gasket within 20 minutes without the need to disconnect the battery and using common household tools only. But when it comes to the ventilation system, then… (with EN subs) |
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Post by privatepaddy on Mar 7, 2013 15:21:32 GMT
Maybe not on German cars but on US cars, almost all had relays for high speed. Not sure on Japanese vehicles. German, UK, French, Italian, Czech and Japanese, maybe more but I hadn't worked on other vehicles. I have never worked on a French car so I would not stick my hand up and give advice, but that's just me. I have however worked on an earlier model to SDs' albeit likely mine has two extra cylinders i like my sixes. Time was blower fans had 2 wire connections and vehicle earth, then they got fancy  |
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Post by GTCGreg on Mar 7, 2013 15:22:18 GMT
German, UK, French, Italian, Czech and Japanese, maybe more but I hadn't worked on other vehicles. you could be correct. I haven't worked on many UK, French, Italian, Czech cars. Looking at some wiring diagrams, it appears Toyota usually controls the heater blower through the return (ground) side of the motor. |
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Post by c64 on Mar 7, 2013 15:31:34 GMT
German, UK, French, Italian, Czech and Japanese, maybe more but I hadn't worked on other vehicles. you could be correct. I haven't worked on many UK, French, Italian, Czech cars. Looking at some wiring diagrams, it appears Toyota usually controls the heater blower through the return (ground) side of the motor. That's pretty common since the resistor array and the switch don't need a special insulation. Worst case scenario in a short circuit is the fan running full speed. Same for the fog and brake lights of most cars. A friend had almost torched his Citroën when the brake switch had snapped in half and the metal bits had touched the brake pedal. Can't happen with most other cars except for UK designed cars. You can tell easily which car has which system. If the brake lights come on when pulling the hand brake and don't work without ignition, they are positive switched. If they work all the time and don't care about the hand brake, they are negative switched. |
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Post by c64 on Mar 7, 2013 15:32:49 GMT
I have never worked on a French car You have no idea how lucky you are!!! |
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Post by privatepaddy on Mar 7, 2013 15:35:45 GMT
I have never worked on a French car You have no idea how lucky you are!!! Yep I do my oldest female sibling had one, she carried a spare distributor around in her hand bag. |
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Post by silverdragon on Mar 25, 2013 10:15:57 GMT
Interesting thread....
I have tried looking for anything amiss..
Ok, so, update, I now have all the functions required, off, slow, medium, fast.
However, they are all "Random"....
As in, I have to select all points on the rotary switch and see which one is doing which to get the one I want.....
I cant find anything obvious....
However, I have been informed that the switch gear on the back of the rotary switch is "Known" to occasionally become loose....
As in, the switch gear my be turning around as its not fully attached to the switch body.....
Thats a get behind the switch thing, as it does not pull out through the dash.
I may try removing the radio as that switch is directly above the radio slot.
Phrench cars....
I do not do any work on phrench cars as no one I know is silly enough to drive one without full warranty....
I hav3 driven a small renault van extensively for work reasons....
The engine was in a random state of wearing out.
It was diesel, it had over 200,000 on the clock...
However, Ford transit vans, the engine in that is well known for its ability to survive going round the clock more times than mickeys right hand with the right maintenance...
renault engines are notorious for a use-by date, it is suggested that have built in obsolescence, they will wear to terminal state at anything over 150,000 miles?...
How useless is that?...
Mercedes and Ford commercial engines are just about getting user friendly by that mileage.
(As in time for first combined Brake system, Cam-belt, clutch, and other engine out major maintenance overhaul..)
I have never driven a "Nice" phrench built commercial vehicle.
I do not like the renault commercial wagons, they just dont feel like they are built with the driver in mind.
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Post by kharnynb on Apr 4, 2013 15:21:43 GMT
Renault is a "when it goes wrong" car, there is no if...and especially with electrical, they tend to be a pain and a half.
I drive a citroen, not the best of cars quality wise, but it has served me well, and you just can't buy anything even close the comfort and extras from any other brand for the price i paid.
citroen engines otoh, especially their diesels are bloody brilliant.
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Post by the light works on Apr 4, 2013 16:07:49 GMT
here, Citroen is considered to be a car for people who are too eccentric for Saab.
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Post by kharnynb on Apr 4, 2013 17:45:17 GMT
heh, here it's the opposite, the xsara picasso we have, and it's follow up the c4 picasso are what you buy if you cannot afford a toyota verso or such "top"brand.
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