front blower mystery-resistor bypass?

[John Kaufmann]

Finding the faulty component is still necessary. Check out whether the switch is bad - it's usually the pigtail connector contacts which burn up - and decide from there. This thread also has switch and dash disassembly info...
https://www.toyotavantech.com/forum/...=switch+blower

Jonny, I checked out the thread you linked, and have to say how impressed I am with your post #7. I went a different way, disconnecting all of the lever cables so that i could pull the HVAC control assembly and work on it. Your approach -- removing the switch without removing the HVAC assembly -- was very nice, and the write-up was terrific.

I will say, though, having gone to all that work (either way), I would just spend the $50 or so (at Autozone) for a new switch, rather than trying to repair the old one or put in a used one.

[Previologist]

Finding the faulty component is still necessary. Check out whether the switch is bad - it's usually the pigtail connector contacts which burn up - and decide from there. This thread also has switch and dash disassembly info...
https://www.toyotavantech.com/forum/...=switch+blower

Yeah I'll get around to it eventually. Thanks for the guidance.

[TheMAN]

Jonny, I checked out the thread you linked, and have to say how impressed I am with your post #7. I went a different way, disconnecting all of the lever cables so that i could pull the HVAC control assembly and work on it. Your approach -- removing the switch without removing the HVAC assembly -- was very nice, and the write-up was terrific.

I will say, though, having gone to all that work (either way), I would just spend the $50 or so (at Autozone) for a new switch, rather than trying to repair the old one or put in a used one.

props to you for figuring out how to unhook all of those cables to take the whole control panel out... there's not a lot of room there, and I didn't bother trying because putting it back in would probably be harder if I did manage to get them out

I just took apart the thing while it's still in the van.. it's not hard to get the fan switch out... mine was burned out too... it's usually the contacts inside the switch that gets corroded or oxidized and cause high resistance, which in turn burns up that pig tail... I found a good pigtail from the junk yard, cleaned and put a nice glob of silicone grease in it to keep those contacts from corroding too... swapped the pigtail out while I fixed my speedometer about 10 years ago... hope I won't have to deal with this again

[TheMAN]

its not the switch itself that scares me, its the prospect of replacing the harness. If I can use the jury-rigged wire to run off a good switch (which I probably have, in my 93) that would be somewhat less intimidating. Being nearly electrically illiterate doesn't boost my confidence.

then become "literate"... the shop manual teaches you how to read wiring diagrams.... if that's not enough, there's always different resources out there that can teach you... it's not that hard, you just have to think methodically and look at things one piece at a time instead of trying to absorb it all at once

[John Kaufmann]

... I went a different way, disconnecting all of the lever cables so that i could pull the HVAC control assembly and work on it. Your approach -- removing the switch without removing the HVAC assembly -- was very nice, and the write-up was terrific

props to you for figuring out how to unhook all of those cables to take the whole control panel out... there's not a lot of room there, and I didn't bother trying because putting it back in would probably be harder if I did manage to get them out

I just took apart the thing while it's still in the van.. it's not hard to get the fan switch out... mine was burned out too... it's usually the contacts inside the switch that gets corroded or oxidized and cause high resistance, which in turn burns up that pig tail...

It's precisely because there's not a lot of room that I wanted it out. I found it exceedingly hard to get the switch out in that small space. That's why I was so impressed with Jonny's write-up, showing in detail how he managed it.

The key to pulling out the HVAC panel was making a tool to disconnect the cables. Of course, having the panel out made replacing two switches (HVAC blower and rear defogger) a piece of cake. [My other reason for pulling that panel was that I was inspired by Dan (man_btc) to add seat heaters. That meant adding switches, one on each side of that center panel -
Seat heater switches mounted(marked).jpg
- wiring them to the seats below and the fuse panel above. Having the HVAC panel out just made all of that easier, but it did require pulling up the whole dash panel. Having seen Jonny's post, I would try that if I had to do it again for just the blower switch.]

[Previologist]

then become "literate"... the shop manual teaches you how to read wiring diagrams.... if that's not enough, there's always different resources out there that can teach you... it's not that hard, you just have to think methodically and look at things one piece at a time instead of trying to absorb it all at once

Well becoming electrically literate and learning to rebuild motorcycle engines are both on my short list of things I never ever wanted to learn, and I'm already trying one of them this summer (against my better judgement).

[TheMAN]

desperate means needs desperate measures...hardly anyone wants to work on these vans, and if you're going to fix it right, you're going to have to force yourself to learn how to read wiring diagrams, like it or not

[Previologist]

The only reason I started rebuilding my motorcycle is because it was dead and would cost thousands to have repaired. It remains to be seen, if I ever finish, whether I've done any good or just wasted a few hundred dollars in parts.

Problem is I'm not desperate, because the blower isn't dead. As long as the blower works on high, I have heat and cold and therefore a reason to procrastinate. Once I finish murdering my bike I will take a look back over this and related threads and decide if I want to proceed.

[Previologist]

Well the good news is I took my bike engine apart and put it back together and it ran afterward, though not very good, and I still need a new bike or new engine.

The bad news is the high power on my blower (which is all I had) has been acting up and not worked a couple of times. Naturally this happens 2 days before I have to drive cross country and need the a/c. Hopefully its just a minor connection issue and I can continue procrastinating on learning to read wiring.

Edit: Its the blower going bad. Hopefully I can keep rapping it back to life for one more week until I get back to my garage. If not it's going to be a very warm drive.

[Previologist]

Is there a strategy that would help keep my dying blower alive a few days longer longer, like keeping it on at all times versus using it little? Since this is a brush issue, I presume using it as little as possible would extend the brush life, but I'm also afraid every time I shut it off I won't be able to jar it back into action.

Probably a no win choice, huh?

[John Kaufmann]

Wayne, in the course of this thread - over many months - several people, based on painful experience, have said your symptoms sound like the blower switch. I have seen no indication otherwise. That does not mean the problem is not the blower, but please remember that people take precious time to share their experience because they want to help. (Get-help/give-help is the way these forums work.) At some point, after seeing that their suggestions make no difference, there is a natural tendency to feel that time spent was wasted, so people give up trying to help. Sorry.

[Previologist]

This is a new problem, starting 2 posts ago John, I just tacked it onto this existing thread. My googling tells me its a brush problem. The blower stops working and I have to give it a smack on the side of the housing for it to start up again. Sorry I thought I was being more clear about that.

Don't think I'm not grateful for the advice on the original problem just because I haven't addressed it. One must choose one's battles and that's just not one I've been ready to tackle, especially since the blower worked fine on high until the brushes started going out.

[Jonny]

With nicer temperatures coming up soon in the Fall, those couple of months would be an ideal time to fix all the blower system problems prior to the arrival of Winter. Your vehicle has had plenty of battles from which you have had to choose, and this just might be an important one to not put off too much longer. Fix the blower motor first to eliminate that problem item under the hood, then start dismantling the dash to get to all the wiring and the switch. If the dash and wiring part of this fix is intimidating I am willing to dismantle my dash and take pics to post on here as needed. However, my van is parked on the street and after Nov 1 you'll be SOL!

[Previologist]

I appreciate the offer but wouldn't want you to go to that much trouble quite yet. This chore is on my radar, but it's on the "to do, if I find time and feel up for it" list. I've been away from home and garage for almost a year so ahead of it on the "Must Do" list now that I'm back are things like stain the deck and as much house as possible, other outdoor chores, possible timing chain on my 4runner, and more. I will at least use the good weather season for attempting to take the switch out of my parts van (if it works), and if I can get that done it will be a step forward and I'll have a better idea what I'm getting into. Its the wiring part that bothers me more, but maybe once I get at the switch it won't seem so bad.

OTOH over the 20,000 miles and 2 years I have on this van I've found very little need for multiple blower speeds. The lowest speed on Previa blowers does almost nothing and wouldn't be missed by many, and adjusting the vents and temperature control accomplish much of what I have ever needed.

I definitely have to replace the blower though and I have to see what the previous moron did to my blower housing, which doesn't even close all the way. I wouldn't be the least surprised if he installed the wrong blower or something equally idiotic.

[Previologist]

Pulled the switch from my parts van which was pretty simple because the dash is partly disassembled already (except for finding that one screw that holds the switch in because I was looking underneath, not above the switch). Got it out and...yay...it does work but it shows obvious signs of overheating, and even has a small crack there. But I've seen worse, and maybe when I pull the one from my 97 I can patch together one unscorched switch. Otherwise I'll just use it until it breaks.

The real elephant in the room is the harness. I will have to remove the driver side kick panel or whatever you call the panel under the steering wheel to even see where that goes before I decide if its something I want to tackle. I suppose creating all new wiring from the switch is an option too, which sounds equally unappealing to an electrical incompetent. But first things first. I'll see if I can trace that harness in the parts van.

[Previologist]

Things are looking up. Got the blower and housing pulled from my parts van, and now that I can see the whole situation on that one I have renewed hope for a happy ending. Since the clown chopped the blower wires off AFTER the blower assembly connectors, unless he did something clownish between the connectors and the dash switch that I just can't see yet (and that seems unlikely), it should be fairly simple to wire it up for all speeds again...In fact I can probably just install the entire blower housing, resistor and harness from the parts van as a unit and just plug her in. Or so I hope. Will be a bit before I get to that job but hope to have this all done by the end of October, if not sooner. In the middle of a major garage overhaul that needs to be done first.

[Previologist]

Surgery is underway...I pulled the blower from my 97 and found the main harness and blower connectors intact! I plugged the 93 blower into it and have all speeds except high. Not sure why, because high worked when I tested it in the 93, and high worked on the 97 (if I banged on the blower housing) before I started but will see what happens when I try changing switches. Its running through the (93) resistor now, but doesn't high speed bypass the resistor?

Correction: It does blow on "high" but I could barely hear it from the cab because it is actually blowing at a similar speed to the lowest setting. Maybe its just because the van isn't running? Anyway this is a better problem than I had before.

Edit: Nope, the same when its running.

Edit #2: ahh, looks like the 93 has a different blower. Weird, but I wonder if that's the problem or not...

[Previologist]

the blower motors appear identical except for how they are designed to mount in the plastic housings, which are configured differently from 93 to 97, so even though the blower seem to be the exact same blower they aren't interchangeable. I opened up the 97 blower and found one of the brushes was totally shot, as expected. So I just lifted the entire brush mechanism out of the 93 blower, and put it in the 97 blower. I wanted to bring the entire innards over, but couldn't see how to get them out. I didn't take the squirrel cage off, and that might be be why it wouldn't come apart.

Switching brushes gave me high speed fan back again. But this must mean the missing low speeds problem is in the 97's blower itself, which doesn't make sense. But it doesn't matter.

Anyone know how to get the entire innards out of a blower motor? If not I have will to order a new one. I thought I might be able to just slip the 93 blower and its plastic housing right in to the 97, but there is a slight configuration difference with how they mount too. The 2 bottom screws are spaced different.

The good news here is that I don't think I need to mess with my switch at all, yet, since I have all speeds (sort of) depending on which blower is hooked up

[John Kaufmann]

... I plugged the 93 blower into it and have all speeds except high. Not sure why, because high worked when I tested it in the 93, and high worked on the 97 (if I banged on the blower housing) before I started but will see what happens when I try changing switches. Its running through the (93) resistor now, but doesn't high speed bypass the resistor? ...

Yes, using the contact of the Front Heater High Relay.

[Previologist]

That's what I thought. Sometime after I tested the 93 blower in the 97 and it blew very weakly on high setting, I had a suspicion that I had not hooked up the connector that goes directly into the blower. I may have only hooked up the 2 connectors that go to the blower subharness. If I'm right, could that be why the high setting only blew very weakly?

It doesn't matter though. I apparently have to buy a new blower anyway. Thinking of trying the cheap VDO blower.