charge trek VII - 'the unloader'

[tim eh?]

... from episode IV ....




-what does the 'unloader' relay do? I keep seeing it in wiring diagrams.




well... this is the unloader relay.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6270&stc=1&d=1226690723

i still don't know what it does, but i'm pretty sure i need a new one.

there is no continuity between any of the terminals.

here it is in a wiring diagram... i was going to pull out the cluster but i think i'll deal with the easy stuff first.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6271&stc=1&d=1226691748

tiger put me on the right track...

it's also hooked up to the dinky euro horns the PO installed.



have ordered one from the dealer that he thinks is a match - the numbers don't match anything he has but he thinks he has the right one.
shogun, may need you here...

here is the topside, sorry for the photo.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6272&stc=1&d=1226691297
that is ...

602.039

61.36
1388745

pretty sure it is #3 here (http://www.realoem.com/bmw/showparts.do?model=HC23&mospid=47402&btnr=61_0579&hg=61&fg=25) - could be #2 but the colour of #3 matches the one i have.



i'll dig around for that 'uncoupling diode' but otherwise i'll cross my fingers and hope it's the problem, not a symptom. i like the smell of this tho.

what does it do anyway? i noticed in later models (bentley 610-1) it is the terminal 'r' where i believe voltage is measured for the obc.

TBC...

[tim eh?]

i think this is all the result of the PO's 2nd alarm, dinky horn job and ignition switch replacement.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6274&stc=1&d=1226697972
http://www.bimmernut.com/forum/attachment.php?attachmentid=6273&stc=1&d=1226697972

this job was tucked away, i only just found it now even tho i have been down here before a couple of times.
i think one wire (blue/violet) has to do with the horns... but the other one i'm not sure... unless...
http://www.bimmernut.com/forum/attachment.php?attachmentid=6275&stc=1&d=1226698086

i think that other wire is only blue but it may have brown or orange in it.... i must confess i am slightly colour blind with some combinations :D scary huh?

maybe something to do with this diode i am looking for that is supposed to be under the dash somewhere.... maybe it is the diode....no...

http://www.bimmernut.com/forum/attachment.php?attachmentid=6276&stc=1&d=1226699258

i have no idea if this is what i am looking for, but whatever it is it's supposed to match my interior?




oh yes... episode vi :D

Car stereo shops has those rings for thick gauge wires...

i beg to differ... most car stereo shops...




*- oh yeah... the unloader kills power to non vital electrical components when starting so that all the juice goes to the starter.
**- .... i think....

[tim eh?]

wait.... just.... a ..... second.....



i use the obc code alarm.

the first time i discovered the hood sensor and factory horn was around 8am one saturday morning, my neighbours were not happy.

soon after that my first alternator died....


edit- actually..... there is no doubt in my mind when this thing got fried.

http://www.bimmernut.com/forum/showthread.php?p=286252

btw- i don't go there anymore :D


i have to do other touch up work anyway :D:D:D LMAO





TBC...

[tim eh?]

oops... i had the meter set too low.

85-86 = 100 ohm
85-87 = 1000 ohm
86-87 = 1000 ohm
30 = nada

#3 i think, so maybe it's ok then? looks ugly.

how do i test this?

[Tiger]

put positive to 30 and ground to 87 and you should hear a click... if so, it works.

[Ross]

put positive to 30 and ground to 87 and you should hear a click... if so, it works.

No. If it clicks the coil is good. The load contacts may still be bad, stuck or have high impedance.

[tim eh?]

no click.

[Tiger]

oops... my mistake... the 85 and 86 should make it click. Tim, make a rig so when you power it up, you can measure resistance between 30 and 87.

[attack eagle]

http://www.bimmernut.com/forum/attachment.php?attachmentid=6275&stc=1&d=1226698086

That is the clutch switch connector, and the factory bypass for automatic cars.

not an issue. :)

---------------------------------------------

standard bosch (now tyco) relay pin setup.
http://www.the12volt.com/12voltimages/addremacc.gif

hope that explains how to test it.

[tim eh?]

That is the clutch switch connector, and the factory bypass for automatic cars.

not an issue. :)

---------------------------------------------

standard bosch (now tyco) relay pin setup.

hope that explains how to test it.

thankyou i was going nuts trying to figure out what that was -

even if i can't fix the car i'll have learned a pile about electrical stuff thanks to you guys.


...make a rig so when you power it up, you can measure resistance between 30 and 87.

my rig - i call it 'the exorcist'
http://www.bimmernut.com/forum/attachment.php?attachmentid=6278&stc=1&d=1226760250

ok still no click and no reading between 30 and 87.

the relay looks pretty fried.

when the weather clears up i'll test the plug terminals, don't feel like setting up my tent. the terminals look good at least...
http://www.bimmernut.com/forum/attachment.php?attachmentid=6279&stc=1&d=1226760250

would be cool if it was just the relay... but i'd really like to find this decoupling link too.
i don't get it - why is it 'natural colour'? i'm starting to go crosseyed looking at the etm.



i feel like i'm getting closer....

[Tiger]

No No... power up the 85 and 86

[tim eh?]

No No... power up the 85 and 86

sorry i wasn't clear


bat+ to 85
bat- to 86

no click

no reading 30 to 87


edit - OOOPS

looked at AE's chart again... LMAO

ok new test, shouldn't make a difference

bat+ to 86
bat- to 85

same results



even if i can't fix the car i'll have learned a pile about electrical stuff thanks to you guys.


LMAO :D

[Tiger]

Mmm... that is really dead... so what does that relay control?

[tim eh?]

Mmm... that is really dead... so what does that relay control?

from what i can find it limits power to the electrical system when starting

from http://www.justanswer.com/questions/12dpp-hello-2001-vw-gti-1-8-turbo

"The unloader relay comes into play when the vehicle is started. Power supply to the electrical consumers is cut to prevent excess draw on the battery while the starter is being operated (a huge consumer of electricity). The consumers that are affected are the ones that you have noted."


i really have to find that tiny diode connector thing.

i'm thinking i could probably run without it (the relay), but i have one arriving next week anyway.

[tim eh?]

OOOOOOPS!!!!!! wait...

:D


The relay clicks with power from 86->85.... so sorry, my bad....

I measure .5 ohms resistance between 30 and 87


But wait, there's more!

I get the same readings on this other one, which is another unloader.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6281&stc=1&d=1226784448http://www.bimmernut.com/forum/attachment.php?attachmentid=6282&stc=1&d=1226784448

here's a schematic for my front power box.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6280&stc=1&d=1226784479

K9 (the unloader i just found) sits in this plug, notice anything on terminal #2?
http://www.bimmernut.com/forum/attachment.php?attachmentid=6283&stc=1&d=1226784448

here's a schematic...

http://www.bimmernut.com/forum/attachment.php?attachmentid=6284&stc=1&d=1226784811

so the suspicious terminal leads to F12 and F16...

wait a sec....

lets look at this photo again...

http://www.bimmernut.com/forum/attachment.php?attachmentid=6279&stc=1&d=1226760250

F16 goes to the seats (power and heat)

before anyone jumps to any conclusions, it's not going to be my heated seat repair... this problem has obviously been around for much longer than that.

but that fuse on F16 is very suspicious, wouldn't you say?

TBC...

[Claude]

from what i can find it limits power to the electrical system when starting.

You're right, that's clear if you look at the Bently page EWD-65 drawing.. but according to the Bentley 1989 car does not have those unloader relay, just 1990 and your car is a 1989 !!

Anyway, that relay if it really exist on your car is not in the electrical path to your are trying to debug.

A simple test to do to confirm that your alternator is good would be to raise the actual lead coming from the cluster to the alternator D+ terminal and to bring here instead a 12 volts directly from the battery + pole (bring to volts to the feeder winding through the voltage regulator of the alternator) the time to do your loading tests (run the car, activated everything, see if voltage still drop after 2-3 min... or not) if it's OK you will know where exactly to look for your next step.

[tim eh?]

You're right, that's clear if you look at the Bently page EWD-65 drawing.. but according to the Bentley 1989 car does not have those unloader relay, just 1990 and your car is a 1989 !!

Anyway, that relay if it really exist on your car is not in the electrical path to your are trying to debug.

A simple test to do to confirm that your alternator is good would be to raise the actual lead coming from the cluster to the alternator D+ terminal and to bring here instead a 12 volts directly from the battery + pole (bring to volts to the feeder winding through the voltage regulator of the alternator) the time to do your loading tests (run the car, activated everything, see if voltage still drop after 2-3 min... or not) if it's OK you will know where exactly to look for your next step.

on the '89 the unloader is connected to the diagnostic connector at terminal 12... see page 96-ewd (http://www.bimmernut.com/forum/attachment.php?attachmentid=6271&stc=1&d=1226691748).

i think i understand how you mean to test the alternator. could i hook up my power pack to it instead of the battery?
if i do that what do i do with the negative clamp on the power pack?

[tim eh?]

ok, (deep breath) I want to approach another angle because something is popping out at me. As much of a newb as I am, I trust my own work more than the PO's, in some cases more than a couple of local 'pros'. (*-but that's really not saying a whole lot) I'm not ruling the seats out, I just think there is a connection to something else.... this burned out ihkr (http://www.bimmernut.com/forum/attachment.php?attachmentid=5756&stc=1&d=1215710986) maybe...


http://www.bimmernut.com/forum/attachment.php?attachmentid=6284&stc=1&d=1226784811

ok so the unloader relays, along with the ihkr, connect to the power supply through 2 partial links (...is that maybe this 'uncoupling diode' (http://www.bimmernut.com/forum/attachment.php?attachmentid=6276&stc=1&d=1226699258) I am looking for?), B and G.

A goes to ignition pos3 ('start') and C goes to pos2 ('on').

http://www.bimmernut.com/forum/attachment.php?attachmentid=6285&stc=1&d=1226789053


I don't know what I am seeing but there is a connection here I think.

How about the readings I get on those unloader relays?
Is 0.5 ohms about right? shouldn't they be different?

[Claude]

i think i understand how you mean to test the alternator. could i hook up my power pack to it instead of the battery?
if i do that what do i do with the negative clamp on the power pack?

It's possible (negative clamp to ground), but you should'nt (otherwise the voltage regulator may not work properly if the output voltage of your power pack differs fa bit from the voltage of your battery positive post), i think you'll be better off with the battery positive directly or if you prefer through a small lamp (ex: 5 watts) as buffer if you are afraid to bust your alternator. Roughly the way the voltage regulator works it compares the output voltage of the alternator (the one that appears on the B+ terminal) with the one that appears on D+ (from the battery) and as long as the D+ terminal is lower than 13.5 v the regulator lets the current pass in the feeder winding of the alternator (lets it generate output voltage / lets it charge the battery) oterwise it cut the current flow in the feeder winding (no longer charge). You see the picture ?

[tim eh?]

It's possible (negative clamp to ground), but you should'nt (otherwise the voltage regulator may not work properly if the output voltage of your power pack differs fa bit from the voltage of your battery positive post), i think you'll be better off with the battery positive directly or if you prefer through a small lamp (ex: 5 watts) as buffer if you are afraid to bust your alternator. Roughly the way the voltage regulator works it compares the output voltage of the alternator (the one that appears on the B+ terminal) with the one that appears on D+ (from the battery) and as long as the D+ terminal is lower than 13.5 v the regulator lets the current pass in the feeder winding of the alternator (lets it generate output voltage / lets it charge the battery) oterwise it cut the current flow in the feeder winding (no longer charge). You see the picture ?

Yes, I think I see.

If the D+ terminal is sitting at 1.5V then, why is the voltage regulator cutting the current flow?

wait...

maybe I should measure the voltage at D+ for a little longer, see what it does when the system drops 3 minutes in....

Still, there must be something whacked happening in that circuit that runs through the unloader relays.
I'm beggining to see a connection in all those little burn marks and the final stage sword burnout i had... i think...

I'm not sure about the colour coding in those etm diags... ws is black and sw is white? is that right?

*- and are those readings normal on those relays... 0.5ohms between 30 and 87? when powered?

stay tuned... i sure hope you guys are all sticking around...