power window wiring

Hi Old Spark!just like you say it.I totally had a different picture of how it must be done.Howies diagram that he sent me made it very clear.the switches almost work like the double relays that we use for mercedes benz single control wire.Do it once,do it right - This means no short cuts. You never get paid twice for having to do the job twice because it wasn't done right the first time.

GOOD! I was certain it is [i[shortless tho I was too lazy to check. But I am aware of short possible switch wiring, however that can usually be solved with some rewiring. And the relays should be exactly the same as the "raw" switches they replace. It's only the thing that flips the switch that varies - ie, a human hand or an electro-magnetic coil. My oft preached advantages or desires for relays include: - take hi-currents away from switches; - minimises heavy current wiring & switching (eg, batt thru fuse and then thru relay contacts to the motor); - additional controls are easier to add - use GND switching else +12V via isolating diodes from controllers (switch, RemoteOn, ACC +12V, charge light) to energise the relay(s); only low currents are involved, typically under 250mA      - relays are easier & cheaper to replace than switches (tho in practice, with the reduced switch current both the switch and the relay will probably last the life of the vehicle. My ute turns 50yo this year). - (ergo...) spare SPDT relays solve most related failures. - there's a far greater range of switches that can supply relay coil currents and they needn't be large. There is limited selection for higher current switches. NOTE that the above is iaw my usual doctrine Everyone has a right to my opinion, but you should find most agree but explain differently. I also like how adding extra controls is simplified... No need for an extra high-current switch, a CPU or sensor can provide +12V to the relay coil via a 1N4004 etc isolating diode. Sure, some thought is needed if different power circuits are used, but instead of using 10A or 30A etc diodes in the power feeds, use battery +12V via a fuse for motor power and each coil-switching +12V input comes from its own supply (+12V or IGN or ACC or HU) via the usual isolation diode. Ground switching changes the above - eg no need for isolation diodes EXCEPT if the inputs need to be independent. Connect the relay coil GND (85) to each grounding input but only add diodes so a GND does not effect others - eg, door#3 triggers different circuits to door#1 and it should not turn in the aircon anyway... But yeah, relays for high current or remote or complex switching applications. I usually have relays switch the hotside (+12V to 30 etc) but of late I find GND signalling be the most practical with digital circuits in mind (ie, CPUs etc tend to use GND aka "Open Collector" switching), however I tend to prefer hot switching and control in automotive situations. (GND switched +12V hot horns are perfect, but GND-switched lighting circuits seemed to provide most faults...)

I am thankful for the information Old Spark!tell me,is it necessary to put a fuse on common 30 to the motors while it already has a fuse on 87 to battery source? The same question goes for 86 +ve switching from ignition 12v?Do it once,do it right - This means no short cuts. You never get paid twice for having to do the job twice because it wasn't done right the first time.

Only 87, (batt) 25 amps and 86 (ign) 2 amps.

Yeah (Howie), a fuse protects ITS downstream distribution. IE - all items downside of a fuse shall have current ratings NO LESS than that fuse... until another fuse takes over.    As to what protection (fuses) to use varies with taste or application.   EG - for some a common circuit breaker for all windows is fine, but if my girlfriend's window has stalled because of some Inland Taipan's jammed neck I'd still want to to be able to close my window - maybe to light a smoke even if that smoke becomes my last. Hence my usual superfat & unblowable flink supply (typically using 60A - 100A flinks) which later splits into each motor's self-resetting circuit breaker supply. I expect the same distribution in my next 4-door vehicles.    And kiddies, search the Inland Taipan aka Fear Snake - it's all true!

Yes but in practise Peter, I would wire it as my diagram, as I have for the last 45 odd years of powering windows, locks etc. Come to think of it, that 1-2 amp fuse I mentioned for the ign feed to 86, never actually done it. Gilding the lilly. If you wanted to go OCD split the 30 wire and a 15 amp fuse to each of the two driver switches. BUT.....

Coil fuses - I've never bothered. Sometimes I consider a thin cable section - sometimes #85 to GND - as the fusible link. Otherwise I use sufficiently heavy wire so the IGN or whatever fuse looks after it. However I have fuse-protected the line for source protection. My distributions usually stem from wanting the lowest voltage drop whilst minimising copper & cost. For decades I've added headlight relays - usually taking +12V from alternator instead of the battery - but in later years I incorporated source independence and redundancy with simple repair methods. EG - left & right beam power thru separate feeds; replace failed lowbeam relay with nearside hibeam relay. Whilst my headlight left & right (or was it hi & lo?) source distributions each handle way in excess of 100A, my window power is more modest. It's a "standard" blade feed from battery +12V - probably a "master" ATS 30A breaker else fuse - to my passenger side knee mounted window switching box. It houses the 4 micro-DIN relays for my 2-door ute windows, plus two 10A ATS self-resetting breakers - one for each window motor, and I think the terminals & wiring for later control expansion. (FYI - micro-DIN relays are often rated for 16A to 24A etc - not the 30A of their older mini-DIN (cube) relays.) I find it advantageous. A single as long as possible feed of amply sized copper. Then split for circuit independence. I can operate any window irrespective of the state of the others. I remove one fuse to isolate all window power. I have max voltage at motors (or lights or loads) for minimum copper outlay. Plus new projects often add to existing power stubs - no need to ponder OEM distribution nor necessarily add more "master" feeds. My power windows take their +12V from my audio's battery feed.

Actually, I recommend battery fed or battery to internal fusebox and no relay.

Thank you guys! Ill keep everything in mind.Do it once,do it right - This means no short cuts. You never get paid twice for having to do the job twice because it wasn't done right the first time.