Blower motor switch

Your dealer did not put their electrical specialist on your van. This part of the circuit is very basic and easy to diagnose. Pull out the heater control so you can access the wires going to the fan speed switch. For these tests a test light will be more accurate than a digital voltmeter. Use it to check for voltage on all of the wires at the switch. You should be able to poke the probe into the connector alongside the terminals.

You should always find 0.0 volts on the black/orange wire. That is the ground wire for the motor, and that has to be okay because some of the speeds work properly.

Next, you should find 12.0 volts on all the other wires except the one that is switched on. If you switch to the highest speed, you will find the dark blue/gray wire has dropped to 0.0 volts, and the motor will run on the highest speed. Switch it to "off", then check the voltages on the other four wires. You should find 12 volts on all of the dark blue wires. What I am interested in is the voltage you find on the dark blue white wire.

My head was spinning until I read your last sentence. That is what I expected you to find, but I wanted to verify it and not overlook something stupid. That one dead circuit could be caused by a bad connection inside the resistor assembly, but you replaced that already. At this point the solution is unbelievably simple, ... Once we locate the cause. You have a wire between the resistor and the switch, with a terminal on each end. That's it.

Here's the list of things to consider, and I purposely complicated it to make it look harder than it needs to be so you think I'm putting some effort into this! These are in order of likelihood.

1. The terminal at either end of the wire is "spread". That means it was stretched from poking a test probe into it too far, or it became badly overheated. Often the fan motor will start to run when you wiggle the connector. Look for a melted area in the plastic connector body.

2. The terminal became overheated, the plastic connector body melted or deformed, and the locking finger became weak and let the terminal back out. All the other terminals are pulled up to the resistor or switch and plugged into them solidly, except for that one. You'll see the terminal not poked in far enough, and you may be able to pull that wire all the way out.

3. The wire is not crimped to the terminal properly. To be specific, the insulation wasn't stripped back far enough before the terminal was installed. That's a manufacturing problem and would have shown up before now. Or, it became a problem after someone replaced a blackened terminal.

4. That one wire is cut.

If you can't find the cause visually, use your test light and try to stick the probe on the resistor terminal corresponding to the dead wire, just under the front of the connector. Leave the switch in the "off" position. When you find 12 volts there, test next on the back side of the connector body, right on the terminal. If there's no 12 volts there, that terminal is not making contact with the terminal on the resistor. If you DO find 12 volts there, do those same tests on the switch end of the wire.

As a point of interest, the reason I asked you to use a test light is they draw current from the circuit to work. When that happens, some of the voltage, (electrical pressure), is dropped across the resistor, and the rest is dropped across the test light. If 8 volts is dropped a resistor, that leaves only four volts to run the test light, and that's why it's on, but dim. A voltmeter doesn't draw current from the circuit. It simply measures the electrical pressure, just like a pressure gauge measures pressure in a compressed air line, but no air actually flows through the gauge. All you need is the tiniest of a strand of wire, or piece of moist corrosion, and enough voltage can sneak through to show up on the voltmeter. That would incorrectly show the circuit is okay up to that point, but in fact, there's no way you could get enough current to flow through that bad connection to run a motor. Using the expensive voltmeter has lead a real lot of experienced people down the wrong path when a cheap test light would have given the more accurate result.

First let me address the fan motor. Sorry if I'm talking beneath your understanding of electrical theory.

For a circuit to work, current has to have a "complete path" to flow from the battery positive terminal, through all the wires, connectors and "loads", meaning a light bulb, motor, heating element, etc, then back to the battery. Anything that breaks that current path stops the flow of current, and the circuit stops working. We're looking for an unintended break that is causing the fan to not run, but our job is a real lot easier because the motor DOES run on some speeds. That proves 99 percent of the circuit is okay.

What I'm leading up to is intended break in the circuit. That is the switch. Where this becomes unnecessarily-complicated is when they move that switch to an uncommon place in the circuit. We normally think of turning the light switch on in your house, and that applies voltage to the bulb, and current starts to flow. In truth, that switch can be anywhere in the circuit and do the same thing. That has been standard for decades with dome light switches in cars. The 12 volts is always applied to the bulb, but current flow is stopped by breaking the ground side of the circuit with the switch. That is what they're doing with your fan motor, and that is backward from normal thinking and how it was done years ago. There's no advantage or disadvantage to doing it either way. It just requires knowing what to expect for voltage readings during testing.

For your motor, current goes to the motor first, then finds a path through the one resistor in the assembly that you've selected, through that part of the switch, then back to the battery. The resistor limits current flow which reduces motor speed. We totally skipped past one step, testing for voltage at the motor, because we know that part is okay. We need to ground the other side of the motor to make it run, and we do that with the switch. You have five switches built into the assembly, and each one is connected with a wire to its own resistor. Each of four of those switches can successfully ground the motor and make it run. We're looking at the one that doesn't do that due to an unintended break. Where it sounds like it gets complicated is from all the test points I listed. You may have faster results from just looking at the terminals to see which one is not making good contact. To compare this to water flow in a garden hose, if flow has stopped, you could take a pile of pressure tests all along the hose to find where the blockage is, or you could simply look for the kink in the hose.

Please let us know what happens.

Cheers, Ken

Yippee! One in a row! Of all the possibilities I listed, a cut wire would have been my last guess.

P0441 - Evaporative Emission Control System Incorrect Purge Flow

Don't know why that would not show up on every code reader.

You must not have owned many other vehicles. Since back in the '50s, Chrysler has always been the world leader in developing innovations that directly benefited car owners. That includes anti-lock brakes, (1969), AC generator, (Chrysler copyrighted the term "alternator"), (1960), lock-up torque converter, (1977), electronic voltage regulator, (1970), fully electronic ignition, (Dodge: 1972, Chrysler / Plymouth: 1973), computer-controlled ignition system, (1976), domestic front-wheel-drive, (1978), air bags, (late '80s), computer-controlled automatic transmission, (1989).... They even had time delay lights to help you see where to put the ignition key, in the mid '60s. Today that can only be done with a Body Computer.

In contrast, GM is the leading innovator in developing customer-unfriendly business practices. This started with their very nice AC generator with the built-in voltage regulator, (1972), and their first electronic ignition system, the "High Energy Ignition System, (HEI)", (1975) that were self-contained assemblies. Very nice for mechanics who didn't understand how they worked, and they could just pop in a whole new system, but very expensive for car owners who had to buy the whole system instead of the one failed part. Opinions vary as to whether this is an advantage or not. First manufacturer to stop allowing us to buy their radio service manuals so they could lock up all that lucrative repair business for their two grossly-over-priced authorized repair centers. Only manufacturer to have a 100 percent failure rate of their CD players over a ten-year period, (1990s). Only manufacturer to have a nearly 100 percent failure of their rack and pinion steering gears within the warranty period, and their solution was a cheap way out in hopes it would hold up just long enough to get the car out of warranty; then it was the owner's problem to fix it properly. First manufacturer to design computers that if replaced, must come from the dealer and must be programmed by them, at considerable cost. First to build the Body Computer into the radio so the radio can't be replaced with an aftermarket unit. Only manufacturer to build into their scanners the option to electronically "lock" all of the dozens of the car's computers to the radio, so if the radio / Body Computer needs to be replaced, every other computer on the vehicle must also be replaced. That can be done by any disgruntled GM mechanic, and you'll never know it, ... Until the radio fails. That "lock" procedure can't be undone.

I won't even be able to see straight if I start in on all the devious stuff Ford has pulled, from non-alignable cars that couldn't help but tear up tires in 15,000 miles, steering parts that separate, leading to loss of control and crashes, in as little as 15,000 miles, and my favorite, two computers, the instrument cluster, which is the master computer, and the "FEM", "front electronic module", required to blow the horn! Typical repair for a dead horn is $800.00.

As disgruntled as you are with fixing your Chryslers, I feel the same way with the Two Fords I've owned, and the four I'm always working on for my friends and relatives. No one can complain about fit and finish, ride quality, handling, and comfort, but with all the progress we've seen in the last 40 years, we should be able to change the oil a couple of times per year, inspect the brakes and suspension systems every other year, and add gas as needed. Instead, many of my former students who owned GM cars thought it was normal to have an $800.00 repair bill every six months. Well, normal for YOU maybe, but not for me.

I recently retired my '88 Grand Caravan due to severe rust, but I hadn't changed the oil in over 15 years and 150,000 miles. (That is not a recommendation for anyone)! The transmission filter was replaced once, at 85,000 miles, and I dragged a tandem axle enclosed trailer with it to car show swap meets for 15 years. That trailer is bigger and heavier than the van, and I never needed the trailer brakes. My "new" daily driver is a simple '94 Grand Voyager. In the year and a half I've been driving it, I changed the oil twice, replaced two tires, and repaired two amplified speakers. Replaced the very uncomplicated instrument cluster so I could have a tach. Oh, and I did have to replace a rusted steel brake line, but that's typical up here in Wisconsin where they throw a pound of salt on an ounce of snow.

The biggest true progress I've seen is cars today are seriously cleaner, but that is due to careful monitoring by the Engine Computer. The technology to achieve that showed up on every car and light truck in 1996, but no other computers are needed or are involved with that task. All of the technological advancements since then involve complicating things like power windows, heater systems, and the starter system. People buy cars today according to the number of cup holders, whether it has butt-warming seats, interior lights that fade out gradually, (that's very important, you know), motorized doors, and all the other toys and gimmicks the designers tell us we need. Seems few of us stop to think about those past buying decisions when we're complaining about the repair bills. I wouldn't even grump about most of the technology as long as I could still drive the car safely after any of those systems failed. If I can unlock and open a door, turn the steering wheel, get the stupid child-proof, politician-approved shifter out of "park", and get the engine started, I'm happy. I'm REALLY happy in winter when the dash blows warm air on my feet! I really don't mind pushing a slide lever if I'm feeling especially warm or cold. That lever causes an awfully lot less trouble than a push-button telling a computer what you hope it will do. You might have another toy to play with while you're driving, but I can't guarantee that computer will make you comfortable during that drive.

Since the day my '80 Volare was new, it consistently gets 28.3 mpg on the highway. That's a 4,000 pound car with chromed steel bumpers. I'm quite happy that today's cars are cleaner, but with all of our technology, shouldn't they be getting better fuel mileage than one that weighs twice as much, from 37 years ago? Everything else, we're told, is improved. Why not fuel mileage?

By the way, I spent 90 bucks for oil changes, air filters, wiper blades, and other repairs on that car in its first 32,000 miles / 25 years. Today 90 bucks get your name mentioned at the service desk.

So to sum up this wonderful story, I'm sorry you're always having to fix something, but your job should be easier now that you've met us wizards who are here to help you. As I used to tell my students, "you're welcome to like any brand of car you want to, just don't tell me yours is better than mine, ... Unless you can tell me why. You may not care in the least about the things I find important. That can include ease of access for serviceability, parts interchangeability, parts availability, ease of accessing service information, the need to add an unnecessarily-complicated computer to every circuit and system that never needed a computer before, and things like that. In my next lifetime, I'm going to be the CEO of a major car manufacturer. My goal will be to base all design and marketing decisions on the best interest of the car owners, just like politicians SAY they have our best interest at heart.

Hope you have better luck with whatever you're driving, but remember we're here when you need us.