Supra 1987 Blower work only medium and high

Check the blower motor resistor pack - look for a plug in the side of the fan duct right after the fan, one or two screws holds it in. It is a simple device, just several open wirewound resistors in series, mounted on a plate that is an electrical connector.

High speed feeds straight +12V to the motor, but the lower speeds drop the motor voltage through the resistor. The lower speeds usually fail first, because that's when the resistor gets hottest and doesn't get cooled because the air is also moving over it the slowest.

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Yeah, mine did the same thing!

Come to think of it, so did my Corolla GT-S... And my Celica GT-S...

Read Bruce's reply. The easiest thing to do is go to a boneyard and get a replacement fan assy with a good resistor pack. That works on most of the Toyotas...but, I *THINK* this is controlled by the climate control box...and if you changed that, you might have another bad one. Open the old box (if you still have it) and see if the resistor pack is in there...

And then let ME know what you find, cause I guess I oughta fix MINE, too, but it's no rush. I park the car for the winter in a heated garage. The only time I use the heat is on mornings like yesterday, at 48 degrees with the roof off, the windows up and the heat set to 72...

The glove box comes out real easy and then you can see the resistor connector and the blower wheel both.

To check the blower wheel for debris look in the return air inlet when it is in the "recirculate" position.

GL Dan

It Fix, work now...! takes about 5 minutes to fix the problem..

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Tools Required: Medium sized Philips screw driver, Fine sized needle nosed pliers, Soldering iron and 60/40 rosin core, solder, Continuity Checker or Volt-Ohm Multimeter (VOM), Dremel Tool with Torpedo shaped Grinding Bit, Clear quick drying lacquer, Flashlight

Skills Required: Basic Skills

Problem: Fan ventilation switches would only work on med and hi speeds, (Or Similar)

Procedure:

1. Under the glove box locate 3 screws holding a protective plastic panel. Screws are located just below glove box hinge area.

1. Remove screws and take out protective panel.

2. Look for a connector with 6 wires going to it. It is located just about in the center of the glove box area about 8-9 inches (20 cm) above the floor board. This connect is fastened to one of the air plenum ducts under the dash.

1. Locate a single screw to the left of the connector. Remove it.

2. Gently pull out the whole assemble from the air plenum.

1. Disconnect the cable connector from the assembly.

2. You will now be holding a small plastic block with male spade type connectors on one side and 5 wire coils on the side of the block inside of the air duct.

1. The coil of wire which is the smallest, nearest the hole used for the fastening screw, is the "resistor" which controls the low fan setting. Check carefully, somewhere this coil is broken from thermal stress.

Also notice that each coil has a dab of some hard white compound. This is potting compound used to keep the coils from "vibrating" around and shorting out against each other. Try not to break this stuff off if you can help it.

1. Now you need to make a decision....

- Use the fine pair of needle nose pliers to probe at the broken coil. If a large chunk of it breaks off repair may not be possible and you can buy a new resistor assembly from Toyota

or

- Try to solder (connect) the two ends back together.

1. To repair the two ends:

- Use Dremel tool and grinding bit to clean off ends of broken coil wire. The wires I fixed were either insulated or had a black type of "oxidation" deposit on them. Don't be afraid to stretch out about 1 coil length of wire (about .5 inches/1 cm) and grasp it with the needle nose pliers while cleaning it up with the Dremel tool. This wire is pretty flexible and can take the handling!

1. Now for the slightly tricky part. Line up both ends of the cleaned ends so that they are along side each other (in parallel). Use the needled nosed pliers to twist the ends together witrh a 1 to 1.5 turn twist. The cleaned-up, bare ends of each wire need to be touching.

- I tried to do this by butting both ends together, but this arrangement was nearly impossible to solder.

1. Heat up your soldering iron and place it under the twisted bare ends. Feed some rosin core solder into the twist until a large enough blob of wet solder is between the two twists, move the soldering iron away and let the joint cool. Note, this wire doesn't seem to take solder real well, so you might need to try a couple of times!

1. If you have either a continuity checker or a Volt-Ohm Multimeter (VOM) now is a good time to test the two connections that the resistor coil makes contact with. On the VOM, set the Ohms range switch to its lowest setting (x1) and read the meter. You should getting a resistance reading of 1.5 - 2 ohms. If you can't get a reading, check your connections and/or run a test probe over to the solder joint to see if everything is alright at that point.

With the continuity checker, all you will be able to verify is if the connection is complete.

1. If all connections are OK, I'd recommend that you use a clear enamel lacquer to seal/insulate the solder joint and any other "bare" spots on the resistance coil that the Dremel tool might have nicked. This will make sure that nothing shorts out after the resistor assembly is placed back in the car.

1. After the lacquer dries, use the needle nose pliers to reform the repaired ends into the shape of the original coil. The whole thing needs to fit back into the air duct plenum!

2. Repeat steps 1-6 in Reverse to put everything back together.

1. FIGHT ANY URGES TO TRY OUT THE FIX BEFORE YOU HAVE THE COIL ASSEMBLY BACK IN THE AIR DUCT PLENUM. AIR BLOWING OVER THE COILS FROM THE FAN MOTOR ACTUALLY KEEPS THEM FROM OVERHEATING AND POSSIBLY BURNING UP.

Thanks...I guess I know what I'm doing this weekend! ;)

(Snip the repair procedure - which is ALMOST right.)

Okay, now that you've confirmed it's the resistor. But you jumped two steps in front of where I was leading you, now when it breaks again go buy a fresh resistor. New ones are cheap enough, and any decent dealer parts dept. is going to keep a few in stock.

Reason being the resistor pack gets too hot for a repair done with normal lead/tin solder (melting 400F - 450F range) to last very long, and it's borderline too hot for silver solder (500 - 600F). In other words, don't hold your breath that the repair will be permanent...

If the resistor was still clean and untouched and you had an Oxygen-Acetylene torch handy to get it hot enough (roughly 1200F -

1500F) you could silver-braze the repaired spots - that compound will easily take that much heat. But now that you have it tinned with regular solder, if you try silver-brazing over it you are going to have a witches' brew of copper, tin, silver, lead... And I haven't a clue whether it will work for long, but I'm guessing not.

TIG welding would work too, but I have no idea what type of tungsten, shielding gas or filler rod you would use. But if you have access to a TIG welder (and they are fairly rare) and an experienced welder (not for the casual user), I know where to ask that question.

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