Blower Fan Issue, Begging For Help

[Zreberlcoe]

I'm just now getting to some electrical gremlins in my car and I would like to get some input.

Symptoms:
1. Blower Fan continues to work on settings 1,2,3,4 after key has been removed from ignition.

2. Recently with cold temperatures when I start the car and want to defrost the windshield while warming up at idle, the blower fan will come on and off.
Example: I will come out to the car to warm it up and switch the fan on to setting 4 to defrost the windshield, and the damn motor wont come on. A solution I have found is revving the motor to as high of a rpm needed for the fan motor to pop back on.

3. When driving before the engine is up to temperature, it seems, the window switch lights flicker also meaning power to the window motors will flicker on and off.

Diagnosing:
1a. I have a clue from a diagram I am looking at,


I'm thinking the K4 relay is the problem because that could be the reason the blower fan will go on and off. As well as when the key is out the relay could be letting power through since it is hot at all times. As to the windows power coming on and off, I have no idea what correlation that would have with the K4 relay, or what pertains to be the problem. If I'm not wrong the K4 relay is in the fuse box as well.

I have very little knowledge on reading diagrams, and even less knowledge on wiring and electrical, so this is all something I came up with in my head. I don't know how to test a relay, that may be something else you guys could point me in the right direction with as well. BUT I may be over thinking this and there is a simple solution so hit me with it if you got it!

Thanks, Zack.

[Zreberlcoe]

Alright, I have gone through some trouble shooting of my own, and whoever responds to this is going to make sense of it all.

So I started out with reading the diagram that the Bentley book was giving me.



So here's my idea, this is the K7 relay I am suspecting that is letting power in at all times (if you read at the top of the diagram to the right of fuse 20 it says "battery voltage in run from relay K7")



It happens that my K6 relay is identical, meaning same part number. So to test if the relay is the issue I went and swapped K6 into the K7 spot and put K7 in the K6 spot. Remember that while the motor is running and K7 relay in it's original place the Fan switch, AC, and Re-circulation switch all worked. Upon starting the car up with the relays swapped I found that non of the three switches were operating.

This is very odd, with relays swapped that have 100% matching markings on them and physical shape, the three switches did not work. Next trouble shoot was to simply put the relays back into their original places, K7 in K7, K6 in K6. To make sure that when everything in it's original place was working as it had before, I started the car up again and to my surprise the three switches did not operate. I thought I had maybe blown fuse 20, and after checking, fuse 20 is still good.

What. The. Fuck. Is. Going. ON.

My previous assumption was that the relay K7 was staying open after power had been supplied to it causing the blower fan/switch, AC switch, and re-circulation switch to stay operable after the key has been removed. After switching identical relays, and motor running, non of the three switches work. Previous to my relay swap, even with the original K7 relay in it's original spot, and the motor on, the three switches had worked! Now when I had put everything back to the way it was before I started troubleshooting the three switches will not operate!

I don't know where to take this from here. Where should I trouble shoot next? If the relay isn't the issue than what is before the relay that I need to troubleshoot? I am going to keep digging in the bentley for an answer but it's very cold outside tonight so anymore poking at the car is going to have to wait until tomorrow.

EDIT I have maybe found a clue as to why the windows have simultaneously started having issues with the heater fan (refer to number 3 of my symptoms). The window circuit as well as the blower motor circuit share the same ground, "G200". I did mention how the window switches will flicker, this may be because the ground is not propperly secured. I'm going to check this as well as any other components the two circuits share, just to check my bases. But Tomorrow. Cause its cold.

Thanks, Zack.

[DaveSmed]

Good on ya for diving into the schematics like that, and coming up with some pretty good ideas where to look for trouble (like that ground point).

To easily narrow down your problem a bit further, pay close attention to the relays behavior with the key on, engine off as you unplug/plug them in. You should hear and feel a click as the contacts close. Assuming the accessories are still inop, this will at least verify the control side of these relays is working at least half right.

The two relays in question are the infamous "unloader relays", which have been known to cause trouble upon starter replacement, or anytime C101 gets messed with, like with engine swaps. The control circuit is kind of unusual in that one terminal controls the relay by switching polarity, while the other terminal controls it as well by adding/removing +ve voltage.

[Zreberlcoe]

So I took a poke at the G200 ground, it seems nothing is wrong, I'm not sure what I'm looking for in a faulty ground other than not a firm connection.





The K7 relay does make an audible click when inserting into it's slot while the key is in the run position.

[Zreberlcoe]

Well, I think I have found the issue.

In the bottom right is the diagram of the ignition switch.



A hypothesis I went on was the ignition switch was leaking power through terminal 15l (labeled on the diagram). 15l is the only terminal that will flow power in the "on" position, and the windows and blower fan only work while in the "on" position. So if this terminal was to be staying open at all times I could test it and verify that. So I took out my handy dandy tester light and grounded it to the knee bolster mounts, pulled the key out of the ignition, and poked into the 2.5mm Violet wired coming out of terminal 15l, and what do you know:


Ding! Ding! Ding! We have a winner!

[DaveSmed]

So I took a poke at the G200 ground, it seems nothing is wrong, I'm not sure what I'm looking for in a faulty ground other than not a firm connection.

That's pretty much it visually. Tight, clean, no broken wires. If you wanted to verify the integrity with a multimeter, you could perform a voltage drop test. The gist of that is you get as much current flowing through G200 as possible by turning on everything you can find that connects to it, then with a meter with the negative lead attached to a known good ground (pref the -ve terminal of the battery) you probe the various terminals attached to the ground point with the positive lead.

The voltage displayed should ideally be zero, because there should be no potential between grounds.

The K7 relay does make an audible click when inserting into it's slot while the key is in the run position.

Thats good, are the accessories still inop? or are they back to being on at all times?

Well, I think I have found the issue.

In the bottom right is the diagram of the ignition switch.

A hypothesis I went on was the ignition switch was leaking power through terminal 15l (labeled on the diagram). 15l is the only terminal that will flow power in the "on" position, and the windows and blower fan only work while in the "on" position. So if this terminal was to be staying open at all times I could test it and verify that. So I took out my handy dandy tester light and grounded it to the knee bolster mounts, pulled the key out of the ignition, and poked into the 2.5mm Violet wired coming out of terminal 15l, and what do you know:


Ding! Ding! Ding! We have a winner!

Interesting! Assuming this stuff is currently on then, what happens when you unplug the switch? Looking at the other end of C200, that should go to your rear defogger. That acting up as well?

As an aside, poking into wires is bad practice. Make sure if you do so, you put a dab of liquid electrical tape or RTV over the hole.

[Zreberlcoe]

Interesting! Assuming this stuff is currently on then, what happens when you unplug the switch? Looking at the other end of C200, that should go to your rear defogger. That acting up as well?

As an aside, poking into wires is bad practice. Make sure if you do so, you put a dab of liquid electrical tape or RTV over the hole.

I haven't looked at the rear defogger, I've been focusing lower to be honest. But what I also think is that the ignition switch is finicky, meaning tonight I was driving the car and randomly the blower fan will come on and off. There's just one thing that I don't understand, and that is the last several times I start the car the fan and windows won't work, but when I rev the motor up they will pop on. Why does RPM have anything to do with this issue? The only wild idea I can come up with is that the ignition switch gets direct power and when the motor revs up, naturally the full amount of amperage is powered to the ignition switch and flicking 15l on. Because I know I have seen my window switches or lights even, get brighter when I rev up the motor, it's the same way in my dads IX, brothers honda, etc.

[DaveSmed]

There's a couple reasons RPM could be involved. The most obvious one is an increase in RPM as you mentioned bumps up the output of the alternator, increasing the voltage at least briefly. This voltage bump might be enough to overcome a poor connection at the relays and cause them to pull in. Once they are pulled in, they do not require as much to stay held in, which is why they wouldn't turn on and off with the small fluctuation. Also, the ground for these relays is on the engine block. The movement of the engine may electrically "make" the loose ground.

[Zreberlcoe]

Alright I replaced the ignition switch, and the fan still comes off and on while driving. The windows flicker as well. I swapped the relays around, I've stared at diagrams from wedophones.com. I have no idea what else to do!!!! The fan itself isn't the problem because the windows cut out along with the fan!!! SOMEONE WITH REAL INPUT ACTUALLY HELP ME.

edit: also while putting in the ignition switch I cut the plug to the door chime and used as a pigtail for my euro clock install. I had a 6 button OBC before and cut that harness. When I tested everything out, I suddenly had no instrumentation lights what so ever, and believe it's the light switch but I'm not confident because the lights all still work.

[DaveSmed]

Alright I replaced the ignition switch, and the fan still comes off and on while driving. The windows flicker as well. I swapped the relays around, I've stared at diagrams from wedophones.com. I have no idea what else to do!!!! The fan itself isn't the problem because the windows cut out along with the fan!!! SOMEONE WITH REAL INPUT ACTUALLY HELP ME.

edit: also while putting in the ignition switch I cut the plug to the door chime and used as a pigtail for my euro clock install. I had a 6 button OBC before and cut that harness. When I tested everything out, I suddenly had no instrumentation lights what so ever, and believe it's the light switch but I'm not confident because the lights all still work.

I told you that circuit you were screwing with on the ignition switch had nothing to do with your windows or blower, it went to your defogger. I also asked you to unplug it to verify your diagnosis that it was the problem, but you replaced it instead. I told you twice its likely the engine controlled side of the unloader relays, a VERY common e30 problem. (I.e. One you can search for on here.)

I'm not sure what input you need here? You seemed interested in learning about the problem, so I gave info on how to check stuff (like the ground thats fine) and a description on how the unloader circuit works, since its a difficult to understand circuit for newer guys. Beyond that dude... I don't know how to help ya.

[Zreberlcoe]

I told you that circuit you were screwing with on the ignition switch had nothing to do with your windows or blower, it went to your defogger. I also asked you to unplug it to verify your diagnosis that it was the problem, but you replaced it instead. I told you twice its likely the engine controlled side of the unloader relays, a VERY common e30 problem. (I.e. One you can search for on here.)

I'm not sure what input you need here? You seemed interested in learning about the problem, so I gave info on how to check stuff (like the ground thats fine) and a description on how the unloader circuit works, since its a difficult to understand circuit for newer guys. Beyond that dude... I don't know how to help ya.

I swapped identical relays around in the fuse box and nothing changed.

[DaveSmed]

You can swap them all day. The relays themselves are fine. The circuit that controls them is not.

[DaveSmed]

.

[Zreberlcoe]

Oh man... I've stared at this diagram too and I don't know what to do honestly.

[DaveSmed]

It IS a damn strange setup. Easiest place to start I think, is pull back the rubber boot on C101, and locate the Black/Green wire on terminal 15. With C101 left connected, stick a bit of wire in the back of that terminal and jump it to ground. Turn the key on and off and verify proper blower motor operation.

DO NOT CRANK THE ENGINE WITH THE JUMPER IN PLACE!

Fire will result. That circuit is supposed to be a ground at all times EXCEPT when cranking, where it is fed positive battery voltage with no fuse protecting you.


Once you establish that the ground side of the circuit is whats giving you fits, check your connections at the starter. In a pinch, you can connect the Black/Green and Black/Yellow wires to the same terminal and it should work OK. Alternately, you could just permanently ground the Black/Green wire after disconnecting it from the starter.