AAZ project update

[vanbcguy]

If you really want to have the AWIC working only when the engine is actually running, use the oil pressure switch at the filter. It connects to ground when there is oil pressure. Use a relay though, it isn't designed for much current!

[Gizmoman]

If I'm using a relay, and the blue wire just for the signal I don't see the difference.
Let me know if I'm missing something though

[CRSMP5]

alts are not cheap is why... cluster pcb are getting old and brittle too..

its not ment to have any load on it... relay i worry will burn something up as its kinda a floating ground circuit... and your forcing it to work as a switch.. it uses the led as a time to charge resistor in theory.. both sides get power and light goes off...

[Gizmoman]

OK, whew - glad I mentioned it before I hooked it up.
I'll change it over to the oil pressure switch (to a relay). It's a pisser though, cause that was my original idea and a guy on a Vanagon site recommended using the blue wire instead.  - Here is a quote from that post "For controlling a couple small relays the alternator blue wire is a way to go. Then as soon as the alternator spins up and the dash led goes out the relays will click on." Obviously he convinced me.

Thanks!

[Gizmoman]

OK, I posted the "blue wire from alt to signal a relay" on the VW forum and recieved this reply. . .

It is ok to use the blue wire circuit to control relays. After all, VW does, in almost every Westy and in many passenger vans. As many as 3 relays, depending on year and options. These are typical automotive relays that use a very small amount of current to activate.

In your case I would use a single relay in the engine compartment and then use the output of that relay to control other relays. That way only the first relay puts any additional load on the blue wire circuit. Then you could put a manual override switch in more easily if needed and the first relay would isolate the rest of the blue circuit from your manual switches.

[vanbcguy]

Yeah I think the point is more that it is a known trouble spot as it is. Lots of VWs out there with messed up blue wires without any additional load. And it is connected to two sensitive expensive things - the cluster and the alternator. So even if you CAN it isn't necessarily wise.

[Gizmoman]

Thanks for the explanation - certainly makes sense.
Hate to admit it but if what I have already done works, I'm going to give it a go.
If it fails, I'll know why.

[CRSMP5]

well what im trying to say is the "power" aspect of it...

0.7v led = little power..

other end is the alt... when not spinning a certain rpm, or power issue to the brushes it acts as a ground.. thru the alt case..

when it spins up to speed it converts from a ground to some power.. in theory all needs is 0.7v.. and then both sides of the led have power and it goes out due to no ground..

now.. see why im calling it a "floating" ground... it is also one of the reasons why when certain "filters" in the alt fail odd things happen.. its never really on/off.. its just there floating between the two..

all the black factory wires turn on via key.. the fuel pump shut off valve is the only circuit thats goofy... you cannot connect it to the alt blue wire or things like rad fan... there is enough juice to keep it running.. as matter of fact fun test for you to try.. test light to pump switch on blue wire..

you can do this on gas car to coil to "fix blue wire" when it screws you (road trip, mechanic 500 miles away).. does not work on a diesel... will not shut off.. yes i did it as works so well on gasser.. but same token.. long long ago.. told a customer miles away who was stuck at a vw garage in se pa.. the test light trick... the garage refused to listen to me.. after hours of dicking around.. they did.. gave him 200$ and sent him on the way for what they learned.. (story in ** below)

and rad fan.. will run till quits turning.. turns into a generator..

so i stay away from that wire.. relay should reduce said issue.. but enough black wire circuits.. heater blower, rear defrost.. should not be hard.. best part.. easy to make sure that circuit works and has not blown a fuse.. while driving too..

i do not see the need for a switch like you are trying to do.. just overcomplicated.. what happens when it fails on a road trip? op switxches fail in *** they spew oil.. but would suck thinking my fan quit running... due to it..

next.. HOW do you plan to use it? its a floating ground.. no power at all type of circuit?? no pressure = ground.. pressure = pushed open.. neither ground or power.. just floating..

trust me floating grounds are bad...

** how to get a garage to pay a customer.. ask him how much cash in pocket.. make a bet... let them think what they want.. when they crack.. and cannot fix it.. they did not understand how blue wire works.. and unwilling to learn.. you force them to put a light bulb between blue wire on alt and coil power... then it charges with no problem.. they must pay up.. and they did... but also thanked him for the education.. that was 98.. before google.. think even predates poortex.. wire was broken by the batt at that connector on a mk2.. where they all corrode..

[Gizmoman]

CRSMP5, What I am trying to do is really quite simple.
If the engine is running, I want the WAIC pump, oil cooler fan (has a thermo-switch), and the WAIC fan on. I don't want them on just because I turned the key to "on".
I put a switch on the diesel pump as well so I can turn it off if I want (although it would nearly always be left on) - again, because I don't want things to be running unless the engine is.

What is odd though, I just did a test - Hooked a meter to the wires that would "energize" when the blue wire pulled in the relay. I started the engine and nothing, then the the dash light went out and the meter showed 12 volts. I figured, cool, it works so I hooked everything up.
Started it again - none of them came on when the light went out

I must have messed up something so I'm going to do the test again and re-check my wiring.

If I understand you correctly, you wouldn't even use the oil pressure switch to do this.

[CRSMP5]

correct.. both are in essance a floating ground...

goto your light switch in your living room... flip to other position really slow till you hear the switch pop/crackle where the light is tryig to turn on/off... that is what they are doig... not good...

do you know how to program in bianary code? this is so far out of scope..but the closet thing i can give a example of..

the basic languge of all digital things is bianary.. think of it as  digital clock.. you can watch th etime click second by second..

now you compair it to a old time sweeping hand of a analog clock.. it never has a "click" or stopping point.. it i slike fluid.. just moves and moves..

the world is analog..

we decript it to digital.. and we get stop points.. causeit i seither a 1 or a 0.. there is no middle..

when you screw up the input on a bianary system.. where it is neither a 0 or a 1.. then it does as it wants.. causeit has nothing assigned to it..

the grounding method your doing is neither a 1 or a 0... its using a analog sygnal.. to convert something digitaly in a method the sensor is not ment too..

a coolent temp sensor has 2 wires.. 1 ground.. 1 to the thing it turns on.. so when closed it is a ground...

oil pressure switch is backwards.. it is open.. floating in the wind.. so not a true on off situation and so cannot be trusted to work..

the alt is a analog sygnal.. requires very litle power for what it does.. sadly way less power is made then you require.. as a true thing... its not a switch.. it is a urrent flow to turn off a light bulb..

i gotta goto work.. give me a couple hours to rethink your idea.. for a solution.. but your current way.. no no good..

[Gizmoman]

Thanks CRSMP5 - appreciate your detailed explanation.
I think the easiest thing to do would be to add another switch in the dash and be done with it.

The one I have now is for the fuel delivery pump and like I said, it will always be on when I turn the key on unless I decide to switch it off.
If I added another rocker switch for the WAIC pump, fan and oil cooler fan, I would just turn it on after I start it.

Maybe I'm just getting old but I remember ignition switches that had three positions, Accessory, on, and start. This van only has on and start

It just seemed like a simple thing - engine running - pump and fans on, engine not running - off.

[745 turbogreasel]

Run a relay off your oil warning indicator lamp.
Supply 'ignition on' power to the switching side
pull AWIC power form 87A NC terminal of your relay

only on with the key, and shuts down if oil light comes on.

[CRSMP5]

but he wants it to shut off with no op.. no op the switch turns to ground... so yes that works... but not how he wants it...

accesory on yours/vw pre mk3.. in mk3 they use it... the smallest gauge wire on the ignition switch oprates the key in hole reminder ding...

using that wire to activate a relay will give you the accessory you seek.. aka only on when key in hole.. or paperclip/blank key.. i use it for radio and parking lights... remove key kills them both... if i need parking lights.. i used to keep a uncut key to slip in the hole... but any thing to hold the rollers open, paper clip for example will turn it on..

no good for what you seek...

the dream circuit ive never installed... cold weather people pay attention.. this for the start it, let it warm yup but no key needed aspect..

30 power
87 pump  requires a diod to power in 1 direction.. so it cannot "loop"
86 or 85 gets toggle type of hot all time power..
other 85/86 brake light bulb...

start car.. flip switch.. remove key... till brakes applied will run.. but once brakes applied.. will turn off relay killing power to pump.. the bulb will work as a ground till brakes applied turning it to power.. i use bulb trick on cruise that lacks cruise pedal switches... not the best way.. but works.. now if your brake light bulbs blow... will not work... but hell nice way to know your brake lights failed... would die like you applied brakes..

so your trying to power the stuff during a after run type of set up.. turns off after engine dies..

honestly.. diode in line with fuel pump feed.. that will prevent run on via the fan.. and only has power when running.. but that diod is key... it will back feed with out it.. the back feed is enough to enigerize/keep relays turned on..

diodes are easy to add.. right at relay.. between 87 and its wire...

like i am saying.. your way over thinking this... in theory what ever your using for your after run set up should power it.. just needs a diode to work right...

if your annoyed with key on to listen to radio and do not want other stuff powered.. make the acc relay off that little wire and use one of the black hot with key things to run the stuff...

p.s. yes i have a ee degree.. but learned "relay logic" way before that... honestly.. the floating ground thing interested me too much as thru my hands on learning of it i never understood why most of the time it worked.. but some times it did not... when you get into binary type of programing with labs of actual see what your doing type of thing.. you do not see the effects.. and its hard to explain..

but reality is.. either on or off.. cannot be held in the middle with no input.. op switch does that.. alt blue wire does that... temp sensor no.. its a varable ground...

the 87a style relays.. 5 prong.. has a 87 and a 87a... 87a is the oppisite of 87... i have not messed alot with them... in my eyes it starts to over complicate things... but he may be right.. i still hate idea of oil switch for it.. but yea ok.. 87a on a op switch.. rember 87a is backwards of 87.. so may work (op switch still floating open when has op).. but make sure it does not draw the battery power dead... a relay being on will kill the batt over 2 nights.. even if every thing else is off..

[745 turbogreasel]

87A type is the same relay, just not missing the 5th tab, so it isn't really more complicated. Quite a few cars have  a spot where you cold  install an extra OP switch, but most of us are gauge nuts.

I once tried to drive an SS Crown Vic which had a weight switch in the seat set to the driver, and killed the engine if you put it in gear.  That SOB got everyone in the shop.
Don't try to get away in a federal car.

[CRSMP5]

i buy bosh duel 87 relays... when they screw it up with 87a ones it sux... so you can buy them both ways...

but 87a gets power when off.. when relay turned on it switches off.. aka power goes from 87a to 87.. or vice versa..

how/why... pop up 930 slant nose headlights... when you turn on the low beams you want them to pop up.. but they also need to pop up on high beams... wish i could rember how i fixed the issue of high beams made them fold down... but it involved the goofy aspect of the 87a relay being screwed up... what i do rember is they triied to use a low beam as 85, high on 86 with 87a to the motor.. slant nose 930s are "after market" and this car was a rebuilt from stripped salvage car.. so had all kinds of odd electrical fun... but man.. that still my most fun ever car to date..

so explain exactly how that succeeds with his goal?

oil pressure switch becomes open floating once pressure... so relay needs to turn off as it lacks ground/power from switch... its floating...

so with 87a... ok turns off the relay... #87a has power then... sweet...

when no oil pressure.. the relay turns on... as the op switch turns to ground... crap.. ok.. no power to 87a.. but power feeds to 87 now... nothing hooked to 87.. ok.. the relay is turned on though.. so 2 days later the batt dead...

see the problem with a 87a relay? unless you run a switched power 30.. from silly black wire circuit he trying to not tap in to.. i see no advantage of any kind.. just use the black wire...