12V. RELAY QUESTION.

[mada1234]

QUICK QUESTION FOR ONE OF YOU LOT OUT THERE,,,,,
STANDARD 12V , FOUR OR FIVE PIN RELAY,, WHAT ARE THE PIN NUMBERS AND CORRESPONDING CONNECTIONS.????
CHEERS IN ADVANCE



MADA.

[T_Diesel]

86 to ground
30 to +ve terminal on your battery
85 to switch
87 & 87A to your hardware that needs the power

A quick google search could have probably told you this.

[mada1234]

LOL, YEAH, DID A FEW SEARCHES WHILE TRYING TO DESCRIBE IT TO A M8 TONIGHT AND DIDNT COME UP WITH ANYTHING AT THAT TIME.
IF I WAS HOME ID OF BEEN ABLE TO LOOK IN MY TOOLBOX LID, I WROTE IT THERE YEARS AGO,, LOL
THANKS HEAPS FOR THAT!

[Tiny]

LOL, YEAH, DID A FEW SEARCHES WHILE TRYING TO DESCRIBE IT TO A M8 TONIGHT AND DIDNT COME UP WITH ANYTHING AT THAT TIME.
IF I WAS HOME ID OF BEEN ABLE TO LOOK IN MY TOOLBOX LID, I WROTE IT THERE YEARS AGO,, LOL
THANKS HEAPS FOR THAT!

STOP YELLING

[mada1234]

HA HA , SORRY, IT'S THIS FLU I HAVE..... (my ears are blocked) lol

[drivesafe]

Hi mada1234, try the link below, it has diagrams and the pin connects for basic automotive relays.

http://www.traxide.com.au/Relay_Info.html

[bansheebuzz]

the correct pin numbers from common bosch 5 pin type relay as no one has yet answered it %100

30 Battery positive(fused/curcuit breaker)
87 To Load, normally open(ie driving lights, thermo fan
87a To load, normally closed(not commonly used when fitting accessories)
86 coil positive(can have direct battery feed, ign feed, or switched feed)
85 coil neg(can have constant neg or switched neg)

there are 2 types of relays that look the same in the common 5 pin. A normally open relay and a change over relay. Normally open(most commonly used) will have 2 X 87 terminals. Change over relay will look the same but the centre pin is marked 87a

The other thing with the polarity of 86 and 85. it is this way because some relays have a diode across the coil to clamp the back emf as the coils magnetic field colapses, if you wire it in the wrong direction it will blow the fuse. Some relays however have a resistor to do the same job, in this case it does not matter, thou you should follow the correct polarity even with a resisted relay as some day you may have to replace it

[macca81]

30 Battery positive(fused/curcuit breaker)
87 To Load, normally open(ie driving lights, thermo fan
87a To load, normally closed(not commonly used when fitting accessories)
86 coil positive(can have direct battery feed, ign feed, or switched feed)
85 coil neg(can have constant neg or switched neg)

there are 2 types of relays that look the same in the common 5 pin. A normally open relay and a change over relay. Normally open(most commonly used) will have 2 X 87 terminals. Change over relay will look the same but the centre pin is marked 87ait

what you have described above is a change over relay. 87a on a normal 5pin relay is normally open. i have never seen a relay that has 2 pins marked with only 87, one is always an 87a. change over relays will say so on the case

[PacMan]

30 Battery positive(fused/curcuit breaker)
87 To Load, normally open(ie driving lights, thermo fan
87a To load, normally closed(not commonly used when fitting accessories)
86 coil positive(can have direct battery feed, ign feed, or switched feed)
85 coil neg(can have constant neg or switched neg)

there are 2 types of relays that look the same in the common 5 pin. A normally open relay and a change over relay. Normally open(most commonly used) will have 2 X 87 terminals. Change over relay will look the same but the centre pin is marked 87ait

what you have described above is a change over relay. 87a on a normal 5pin relay is normally open. i have never seen a relay that has 2 pins marked with only 87, one is always an 87a. change over relays will say so on the case

Sorry mate,

but bansheebuzz is right.
There are relays with 2x pin 87 on it. Looks like you have seen only change over relais in your hole life.

Chris

[ledgend80]

x3 on the 2 - 87 pins

[drivesafe]

[bansheebuzz]

thats incorrect as you have the descripion for 85 and 86 wrong way round

[drivesafe]

Hi bansheebuzz, with the exception of a handful of specialised relays that came out with a spike suppression diode, relay coils are not polarised so it doesn’t matter which way you wire the coil.

[bansheebuzz]

if you read my earlier post you would have seen that i have already noted that some relays have a diode hence why i suggest doing it correctly, 85 earth side 86 pos, they dont have to be specialized relays, depends on the manufacturer whether they use a diode or resistor. i had a 5 pin relay couple of months ago with a diode

here is the complete pinout designations from mr bosch

From Bosch Automotive Handbook, 3rd edition

Terminal Designations (Excerpts from DIN Standard 72 552)
The terminal designations do not identify the conductors, because device
with different terminal designations can be connected at the two ends of
each conductor. If the number of terminal designations is not
sufficient (multiple-contact connections), the terminals are
consecutively numbered using numbers or letters whose representations
of specific functions are not standardized.

Terminal Definition
-----------------------------------------------------------------------
IGNITION
1 Ignition coil, ignition distributor, low voltage
-----------------------------------------------------------------------
(Ignition distributor with two separate electrical circuits)
1a to ignition contact breaker I
1b to ignition contact breaker II
-----------------------------------------------------------------------
2 short-circuit terminal (magneto ignition)
4 Ignition coil, ignition distributor, high voltage
-----------------------------------------------------------------------
(ignition distributor with two separate electrical circuits)
4a from ignition coil I, terminal 4
4b from ignition coil II, terminal 4
-----------------------------------------------------------------------
15 Switched + downstream of battery
(output of ignition/driving switch)
15a Output at dropping resistor to ignition coil and starter
-----------------------------------------------------------------------
GLOW PLUG AND STARTER SWITCH
17 Start
19 Preheat
-----------------------------------------------------------------------
BATTERY
30 input from + battery terminal, direct
30a input from + terminal of battery II
(12/24 V series-parallel battery switch)
31 Return line to battery
- battery terminal or ground, direct
31b Return ine to negative battery terminal or ground, via switch
or relay (switched negative)
-----------------------------------------------------------------------
(12/24 V series-parallel battery)
31a Return line to - terminal of battery II
31c Return line to - terminal of battery I
-----------------------------------------------------------------------
ELECTRIC MOTORS
32 Return line
(Polarity reversal possible at terminals 32-33)
33 Main terminal connection
(Polarity reversal possible at terminals 32-33)
33a Self-parking switch-off
33b Shunt field
33f For second lower-speed range
33g For third lower-speed range
33h For fourth lower-speed range
33L Counterclockwise rotation
33R Clockwise rotation
-----------------------------------------------------------------------
STARTER
45 Separate starter relay, output; starter input (main current)
45a Output, starter I
Input, starters I and II (Two-starter parallel operation)
45b Output, starter II (Two-starter parallel operation)
48 Terminal on starter and on start-repeating relay for
monitoring starting procedure
-----------------------------------------------------------------------
TURN SIGNAL FLASHER
49 Input
49a Output
49b Output, second turn-signal circuit
49c Output, third turn-signal circuit
-----------------------------------------------------------------------
STARTER
50 Starter control (direct)
50a Output for starter control
(Series-parallel battery switch)
50b Starter control with parallel operation of two starters with
sequential control
50c Input at starting relay for starter I
(Starting relay for sequential control of the engagement
current during parallel operation of two starters)
50d Input at starting relay for starter I
(Starting relay for sequential control of the engagement
current during parallel operation of two starters)
50e Input, Start-locking relay
50f Output, Start-locking relay
50g Input, Start-repeating relay
50h Output, Start-repeating relay
-----------------------------------------------------------------------
ALTERNATOR
51 DC voltage at rectifier
51e DC voltage at rectifier with choke coil for daytime driving
-----------------------------------------------------------------------
TRAILER SIGNALS
52 Signals from trailer to towing vehicle, general
-----------------------------------------------------------------------
WIPER MOTOR
53 Wiper motor, input (+)
53a Wiper (+), self-parking switch-off
53b Wiper (shunt winding)
53c Electric windshield-washer pump
53e Wiper (brake winding)
53i Wiper motor with permanent magnet and third brush (for higher
speed)
-----------------------------------------------------------------------
TRAILER SIGNAL
54 For lamp combinations and trailer plug connections
TRAILER STOP LAMP
54g Pneumatic valve for additional retarding brake,
electromagnetically actuated
-----------------------------------------------------------------------
LIGHTING
55 Fog lamps
56 Headlamp
56a High beam, high-beam indicator lamp
56b Low beam
56d Headlamp-flasher contact
57 Side-marker lamp: motorcycles, mopeds.
Abroad also cars, trucks, etc.
57a Parking lamp
57L Parking lamp, left
57R Parking lamp, right
58 Side-marker lamps, tail lamps, license-plate lamps and
instrument-panel lamps
58b Tail-lamp changeover for single-axle tractors
58c Trailer plug-and-receptacle assembly for single-conductor
tail-lamp cable with fuse in trailer
58d Variable-intensity instrument-panel lamp, tail-lamp and
side-marker lamp
58L Side-marker lamp, left
58R Side-marker lamp, right; license-plate lamp
-----------------------------------------------------------------------
ALTERNATOR (magneto, generator)
59 AC voltage, output
Rectifier, input
59a Charging armature, output
59b Tail-lamp armature, output
59c Stop-lamp armature, output
61 Alternator charge-indicator lamp
-----------------------------------------------------------------------
TONE-SEQUENCE CONTROL DEVICE
71 Input
71a Output to horns 1 & 2, low
71b Output to horns 1 & 2, high
72 Alarm switch (rotating beacon)
-----------------------------------------------------------------------
INTERIOR
75 Radio, cigarette lighter
76 Speaker
77 Door-valve control
-----------------------------------------------------------------------
SWITCHES
----------(Break-contact and changeover switches)----------------------
81 Input
81a 1st output, break side
81b 2nd output, break side
----------(Make-contact switches)--------------------------------------
82 Input
82a 1st output
82b 2nd output
82z 1st input
82y 2nd input
----------(Multiple-position switches)---------------------------------
83 Input
83a Output, position 1
83b Output, position 2
83L Output, left-hand position
83R Output, right-hand position
-----------------------------------------------------------------------
CURRENT RELAY
84 Input, actuator and relay contact
84a Output, actuator
84b Output, relay contact
-----------------------------------------------------------------------
SWITCHING RELAY
85 Output, actuator (end of winding to ground or negative)
86 Start of winding
86a Start of winding or 1st winding
86b Winding tap or 2nd winding
----------(relay contact for break and changeover contacts)------------
87 Input
87a 1st output (break side)
87b 2nd output
87c 3rd output
87z 1st input
87y 2nd input
87x 3rd input
----------(Relay contact for make contact)-----------------------------
88 Input
----------(Relay contact for make and changeover contacts (make side))-
88a 1st output
88b 2nd output
88c 3rd output
----------(Relay contact for make contact)-----------------------------
88z 1st input
88y 2nd input
88x 3rd input
------------------------------------------------------------------------

[drivesafe]

Hi again bansheebuzz and I have read your posts, this does not change the fact that they are a non standard relay and are only required for direct replacement of some relays already use by a number of vehicle manufacturers.

Even with those vehicles that have the diode suppression type relays fitted, here in Australia, if one fails and needs replacing, an ordinary relay, suppressed or otherwise, can be use.

For general use, standard relays are all thats needed and the coils are not polarised.

[bansheebuzz]

a common aftermarket normally open or change over 5 pin relay can be fitted with a diode, i have seen plenty of them

[ledgend80]

i was told to make 86 the power in and 85 the earth weather or not this is correct this is how i wire up all my realys and how i find them to be all wired up on all the machines i work on.
just my 2 cents worth

[drivesafe]

Hi bansheebuzz, I sell relays and to get diode fitted relays, I would have to order them specifically as a diode relay.

When ordering relays from any of my suppliers, I simply order the type of relay, EG Headlight, Changeover, Dual and so on, and they have never come with diodes fitted and I go through thousands of them every year.

If your getting them with diodes, you are either ordering them that way or ordering with the wrong number.

As posted above, it is not necessary to use suppressed type relays in Australia for day to day use.

[bansheebuzz]

i go through thousands of them every year too! but i dont get them with diodes, my point is there out there and if you post incorrect info it could lead to people bashing there head against the wall wondering whats wrong when the fuse keeps blowing, all because 2 wire on the wrong way

[rapid80]

I only ever use a diode relay if its a circuit wired to a plc or ecm. 99% of wiring that the average 4x4 home handyman will do won't be so it doesn't matter which way the coil is wired in. If your playing with diode relays chances are your smart enough to look at the schematic that is etched into the relay so will know which way to do it anyway. I agree with bansheebuzz that's the right way to do it but for the layman in 99% of applications it doesn't matter.

[T_Diesel]

I only ever use a diode relay if its a circuit wired to a plc or ecm. 99% of wiring that the average 4x4 home handyman will do won't be so it doesn't matter which way the coil is wired in. If your playing with diode relays chances are your smart enough to look at the schematic that is etched into the relay so will know which way to do it anyway. I agree with bansheebuzz that's the right way to do it but for the layman in 99% of applications it doesn't matter.

Correct, well said. These electrical threads always bring out the self proclaimed electrical experts.

The poor bloke who started the thread probably only wants to wire up a set of spotties or airhorns, and then gets 26 replies on diode relays and electrical schematics which to the layman are just plain confusing.

[chimpboy]

Do you guys have a good reason not to just wire it the right way around to match the Bosch specifications?

I have been caught out by dropping a spare relay in and finding it had a diode across the coil, from what I've noticed they are actually not that uncommon as OEM items on a modern car. Admittedly it only took about three seconds to notice but since then I prefer to wire them so either kind will work.

[drivesafe]

Hi Folks, if you use diode protected relays, and I can’t see why you would go out of your way to get them, then wire them as suggested.

T_Diesel, while I think you specifically use them as you described as protection for supposedly sensitive electronic equipment, if you use a non suppressed relay right next to this same equipment or you put it at the extreme opposite end of the vehicle, in an unrelated circuit, any spikes generated by the relay will still get to the electronics.

The suppression is not there to protect the electronics of the vehicle, every piece of electronics in every vehicle has already got spike suppression built in.

The suppression is the to allow these same relays to be sold and use in the EU, where they have very stringent electronic noise suppression regulations.

Again, the need to wire the coil of a relay in one specific manor is only necessary if you specifically use diode protected relays, which in itself is unnecessary.

Sorry if this does not conform to the thinking of some, but I have no intentions of changing something if it not broken.

[r0ck_m0nkey]

If your getting them with diodes, you are either ordering them that way or ordering with the wrong number.

Or like a lot of people, just recycling bits and pieces laying around which could have come from anywhere.

Hence why it's best for someone who isn't that knowledgable to wire them the correct way just in case. As they sure aren't going to know what's going on if a diode is involved.

[drivesafe]

Hi r0ck m0nkey and I can appreciate that people do recycle, as has been posted above and in those situations it probably pays to know which way to set that specific type of relay up but to state that the info on the diagrams is incorrect is not the case, the diagrams are for bog standard relays, they don’t have polarised coil pins.

As posted, I go through heaps of relays and just out of curiosity I had a look at the schematics printed on the side of the different ones if have instock and low and behold, one of them actually states that pin 85 (-) and pin 86 (+) and the relay is not polarised. Go figure as this does not change the fact the relay’s coil can be wired in either direction.

[bansheebuzz]

it is incorrect

1 because there is nothing to state on the relay whether it has a diode or resistor as internal suppresion,

2 you cannot wire every 5 pin relay 86neg and 85 pos but you can wire every relay 86 pos 85 neg

all relays sold these days will have some form of suppresion, and you certainly aint going to open it up to see whats in there, the fact of the matter is that pin 85 is designated neg and 86 pos for this reason and if you follow the standard then it makes it easy if you change a relay or have to test the curcuit.

[drivesafe]

Now your just making it up as you go along, there is no standard for wiring a relay.

Next ALL relays sold DO NOT have some form of suppression and of these that do have suppression, because of the problems you yourself have raised, and have already mentioned, many relays with suppression added, have either resistor or resistor/capacitor suppression and these are used to avoid the need to have to rewire just to be able to use a diode ( polarised ) relays.

Again, there are NO standards for wiring relays, there are requirements when using diode suppressed relays and therefore it’s a choice of what relay you use as to whether you need to wire it a given way or any way.

Mada1234, by now you probably have all the info you need, confusing or other wise, so I won't waste any more of your time.

[Dooley]

Even with those vehicles that have the diode suppression type relays fitted, here in Australia, if one fails and needs replacing, an ordinary relay, suppressed or otherwise, can be use.

I would suggest against it... they are there for a reason. Back emf isn't exactly healthy if you have sensivite ICs or transistors driving them.

That sort of thinking is like "Oh yeah a 20A fuse is fine so a 25A fuse should also be fine."

[drivesafe]

Hi Dooley, rapid80 has covered that and my hat off to him for trying to protect so called sensitive equipment.

BUT, the use of any form of EMF suppression actually has nothing to do with protecting so called sensitive equipment because there is no sensitive equipment used in the automotive industry.

Every single bit of electronic equipment in your vehicle is already protected by its own built in spike suppression.

To back this point, there are many thousands of people, and I’m sure this includes quite a few on this forum, who use nothing more than a good old fashion unsuppressed solenoid and NONE of them ever has a problem with electronics being damaged.

Dooley this is not aimed at you but there is so much crap out there, usually put out by unscrupulous Isolator sellers making claims that their isolator will protect your vehicle because they have added spike protection.

This is nothing more than a truck load of horse droppings.

If you were to fit one of their device and they hadn’t fitted their wonder spike protection, absolutely nothing would happen to the electronics in your vehicle, BUT the isolator’s own electronics would be fried after just a few operations.

If the penny hasn’t dropped, these isolators need the spike protection to protect the isolators own electronics and they offer no protection to your vehicle and the sellers implication that their spike protection will protect your vehicle’s electronic is nothing more than an advertising con job.

While we are on the subject advertising con jobs, can someone explain how a device the size of a 10 cent piece inside these isolators, can give a vehicle surge protection, when the biggest surge protection device in your vehicle, your cranking battery can’t. And more to the point why do you need surge protection in a 12v DC system?

[chimpboy]

I'm still not seeing why you wouldn't just wire them in line with the bosch pin arrangements and avoid the potential error in the future. Why make such a big deal about it when it is obviously good advice to wire them that way?

If someone asks the simple question "which way should I wire my 12V relays?", which answer is better? Surely it's the answer that works with both kinds of relay. Why is the other answer better?