Landark

The other day I drove to work and my AC was working fine as far as I could tell. When I got in the car to leave I noticed it was hotter than I expected after starting the car. I saw the auto fan speed was on high but I couldn't feel cold air coming out of the vents. So long story short, my blower fan is not blowing at all - not even on low speed. I dug into things today and determined that the fan works when bench tested and using my test light I found that there is no power going to it. The climate display works as it should, I can hear all the actuator doors opening and closing when I change the functions, and I plugged in another control unit I previous bought just in case and it seemed to work fine as well but still no fan (the display on that one is bad but I can still hear the actuators). I ran the internal diagnostic and it had no errors - even when I unplugged the fan..

So my research seems to point to the resistor - but every post I've read where someone replaced it the problem persisted. I don't want to spend $420 on a part to have it not solve the problem. Has anyone else had their fan stop working and replaced the resistor and had it solve the problem? Where is the resistor? I see nothing on the housing from where I can see. Is there any way to test the resistor?

And is it possible that I am heading in the wrong direction? Could it be an ECU problem? Nothing else is wrong with the car that would indicate the normal capacitor failure symptoms.

85,000 kms
Normal climate control
Car was heavily smoked in but the fan looks clean

Yamae

Sorry for your trouble. If it's caused by the dead blower motor controller attached to the motor, this part 87165-50020 is discontinued and not available easily except some stocks in the market as is posted here.

I worry that you can't fix the problem due to the no availability of the part. If I were you, I'd try to repair the unit. It's a high power PWM controller and it has a power MOS FET inside. Replacing it and it's driver can mostly fix the unit. Problem is that this needs some skills and measuring tools.

Another method is to use 87165-50040 or 87165-50050 but these need some big modifications both mechanically and electrically. You can find photos of these here but everything is written in Japanese.

Landark

Thanks for the input Yamae - I am hopeful that it's not the controller simply because it seems most folks will still have 1 speed, or will have had symptoms of some sort leading up to controller failure. Since I've owned the car I've had nothing out of the ordinary with the climate system. It worked one minute and not the next.

I've been thinking more about what to do - if all else fails what about installing an inline power source at the fan connector with a dimmer/voltage controller that would allow adjustment so the fan could still operate at different speeds? I fear the reason for the resistor is to limit the load going to the motor - would I just burn it up that way? Everything else internally still seems to be working.
I mean, ideally I want it to be working correctly, but it seems like that's been made incredibly difficult.

Landark

Just a quick update for anyone who comes across this here.

I found the resistor, it's the little splash of yellow peaking out at the very bottom of the fan shroud below the letter R. I checked and confirmed there is no power going to that either. So that seems to lead back to the controller. I guess it's possible that both mine and the LS400 spare unit I bought at the junkyard are suffering from the same issue. It's also possible there is some sort of wiring issue. I checked the fuses too while I was at it but there doesn't seem to be any specific fusing for the fan. Correct me if I'm wrong.

I dropped it off at the shop I've been using for servicing it today and I'll wait to see what they say.

paulo57509

I wonder if rebuilding the controller is a DIY project?

Yamae

Sorry to say but I have to correct you. There are 2 fuses related to the blower motor as are shown below (top left corner). There are also relays to power the blower motor and it's controlling circuit. Although some of expressions are in Japanese, it wouldn't be easy to troubleshoot without a wiring diagram.

Landark

Wow, I don't know how I missed that, that's incredibly valuable information. Thank you.
I'll have that checked. Of course, a blown fuse would do little reassure me, but it would at least be a place to start.
Again, I really appreciate your response.

Landark

Update: I got my car back from the shop - the fan still does not work. The tech said he had power going to the resistor which I found suspect but before I picked it up I went and witnessed the fan working when everything was plugged in. He hit the temp down button a few times and it kicked on. He said the resistor would get hot and eventually the fan would slow and stop. I was able to use the fan at all speeds while it was running. Because of the lack of available replacement resistors the tech said he would try to find out what was wrong and rebuild it. A few days later I was told he was unable to get fully into it and it wasn't rebuildable. That's when I pulled the plug and went to pick it up. The fan has not worked since I picked it up.

On the way home, my exhaust temperature warning light would flicker on and off. Today I drove it again and when the AC was turned on, the exhaust temp light came on again but stay on. It shuts off when I turn the AC off (note, it's turned on but not blowing since the fan doesn't work).
And after my drive I was parking it and the TRAC OFF light started blinking.

So, do I have 2 problems? The HVAC issue and whatever is causing the TRAC OFF light - or should I be looking at ECU capacitors?

Landark

I'm going to keep updating this until it's fixed.

It's been back at the shop for about 4 weeks now. They sent the ECU off to have the capacitors replaced. I was told everything was fine and they didn't need to be, but I already had the caps and figure it's just a matter of time so I told them to go ahead and replace them. The ECU is back in the car and the blower still doesn't work. The control unit and all 3 resistors I have since acquired were tested by the shop that did the ECU work and confirmed to be working.
The shop went through the wiring harness from inside to outside looking for issues and found nothing.
They are now attempting to replace the fuse/relay box under the hood thinking that is bad. If that doesn't fix it, more searching.
At this point I am willing to bypass everything and put the fan on a dimmer switch.
Since it's been in the shop I've bought another car and that means this one is going to have to go, but I want to get it in 100% condition before then so as not to pass my problem on to someone else. This will have turned into a very expensive issue once all is said and done.
If there is someone who knows where to find the full wiring diagram, even if it's in Japanese, please let me know.

paulo57509

I'm kind of curious...what does the blower controller look like? Is it a big heat sink unit that the blower motor plugs into, similar to this:



This is a new unit that I hoarded for my Acura after I rebuilt the original one after the blower motor stopped working. There is a thermal fuse that's in the internals. It's sacrificial component so once it opens the fan is dead. I'm wondering if your fan controller has a similar fuse. I was told that a dying blower motor will draw excess current causing heat related strain and will blow the fuse. The fuse looks like a small two-lead resistor: https://media.rs-online.com/f_auto/F7127284-01.jpg

fedaykien

Blower Control Module 87165-50010 or 87165-50020

Landark

What I'm referencing as the control unit is the actual in dash control unit - the one with the buttons you press to make things change.
What you're showing is what I would think is the resistor. I am certainly willing to admit I don't know if there is another component I should be looking at.

Landark

That's what I am referring to as the resistor. I tried 3 different ones - but that's also what I was saying isn't getting power so I suspected it was never the problem.

fedaykien

since you're in US, perhaps you can talk first to these guys...

https://taninautoelectronix.com/prod...ontrol-repair/

Landark

The Celsior had been in the shop from the end of October until about a week ago. To their credit, the shop I had it at refused to give up until the fan started working. If you're in Northern VA and need a shop to work on a car other shops won't touch, take it to PBC Automotive in Chantilly.

I had him take the ECU to a place I had called but who were reluctant to work on it. I had already bought the capacitors planning to replace them preemptively. I had no signs that anything else was wrong prior to the fan issue. Once that happened I had the exhaust temp light come on periodically, a flashing TRAC light, and the battery would go dead after a few days if I left the resistor plugged in. The ECU was confirmed to be good, the capacitors were not leaking. I asked to have the capacitors replaced anyway.

With the capacitors ruled out, I was let down since I figured all signs point to the ECU being a problem. But the shop said he wanted dig in farther and test the wire harness to see if there was anything he could find.
In part of the wire harness discussion he mentioned he also wanted to inspect the fuse and relay box under the hood and wanted me to authorize him buying an LS400 box and I said sure.

He never found anything obvious in the wiring harness but he said after replacing the fuse box the fan started working. He said he kept it for a week, taking it out periodically to make sure it would stay working, and that the resistor wasn't overheating, that the battery wasn't draining, and to make sure no other issues were present.
I haven't driven it much since, but in the 25 minute drive home it ran flawlessly. It's worth pointing out that the two boxes are not identical. I meant to take a photo of the LS400 one, but I forgot. I will add it later.

In total I bought:
1 new OEM resistor from ebay; part number 87165-50028 RU458 - it does not look like the one that came on the car, but it's the one the shop put back in. ($448)
1 used OEM resistor from someone in England on ebay listed as: 87165-50010 0kW MAH3095 ($65)
1 new AC Delco blower motor from RockAuto part number: 1581204 ($97)
1 new OEM heater blower motor relay part number: 90987-04002 ($28)
The capacitor replacement cost $250
The used LS400 fuse and relay box was about $250 - I could have gotten it cheaper but there were no 95-97 LS400s in the u-pull-its nearby recently.
All in, with shop costs for both visits, this totaled just over $3,000.

The worst part of all is, after spending that much money, I probably won't get much time to enjoy it. I haven't listed it for sale yet but I'm going to need to do something. We'll see. I really enjoy driving it and owning it - it's so understatedly cool.

Anyway, I decided to take the OEM fuse box apart to see if I could find any signs of failure. I was expecting to find the usual green circuit board and was totally shocked to see that the circuit board is there, but in the old style.
I didn't see anything, all the circuits are intact and nothing really seems off. I took some photos of where it looks like there are flash marks but I don't believe they are related to the fan circuit. I thought it would be interesting to see though. I will NEVER be able to put it back together, but I am keeping it just the same.















Evidence of flash?