Electrics, relays and wires....
Discussion
In my search to track down the bad behaviour of my Griff, I am closing in towards the electrical side of the car.
Does anybody have a good understanding of relays ?
I have an idea that the intermittant fault within my car is being caused by the immbobiliser somewhere, somehow.
After a fiddle with some of the footwell electrics, I noted that one of the relays rattled when shook. Surely this is not the reaction of a healthy relay and possibly is the cause of my fault?
Making a note of the relay specifics, 12v 20/30a 5 pin, I journeyed to Motorworld but was presented with many differing types of relay of similar but not all identical code numbers and sizes. Scared, I went back home without any goods.
How important is it to get the exact type of relay? Although the relay in question is a 5 pin jobby, I noted that the middle pin is infact only connected by a spade but without a wire.
Should I ignore this middle 'misfit' and get a 4 pin or is there a reason that this wireless spade is attached to the middle of the 5 pin relay.
Yours truely confused
Lazy
Does anybody have a good understanding of relays ?
I have an idea that the intermittant fault within my car is being caused by the immbobiliser somewhere, somehow.
After a fiddle with some of the footwell electrics, I noted that one of the relays rattled when shook. Surely this is not the reaction of a healthy relay and possibly is the cause of my fault?
Making a note of the relay specifics, 12v 20/30a 5 pin, I journeyed to Motorworld but was presented with many differing types of relay of similar but not all identical code numbers and sizes. Scared, I went back home without any goods.
How important is it to get the exact type of relay? Although the relay in question is a 5 pin jobby, I noted that the middle pin is infact only connected by a spade but without a wire.
Should I ignore this middle 'misfit' and get a 4 pin or is there a reason that this wireless spade is attached to the middle of the 5 pin relay.
Yours truely confused
Lazy
Edited by lazyitus on Monday 15th January 11:25
Relays shouldn't rattle.
There are all sorts of relay form factors and pinouts, but two that seem to be most common for cars are 5-pin spade terminal connectors with alternative pin configurations. The first sort is a single pole relay with two output pins, these are the most common ones. The second is a single pole changeover relay. These are the same size and shape and have pinouts that are similar enough that you can put one in a socket designed for the other and it will sort of work, but they are not interchangeable. You need to find out what sort of relay you have, and get another identical one. There relay case often has a schematic on the side showing the logical layout so you can confirm the replacement is an exact equivalent after matching the size/shape.
There are all sorts of relay form factors and pinouts, but two that seem to be most common for cars are 5-pin spade terminal connectors with alternative pin configurations. The first sort is a single pole relay with two output pins, these are the most common ones. The second is a single pole changeover relay. These are the same size and shape and have pinouts that are similar enough that you can put one in a socket designed for the other and it will sort of work, but they are not interchangeable. You need to find out what sort of relay you have, and get another identical one. There relay case often has a schematic on the side showing the logical layout so you can confirm the replacement is an exact equivalent after matching the size/shape.
GreenV8S said:
Useful info
So with my rattling relay, is it fairly safe to assume that it could well be the cause for a problem?
Should I disconnect the battery before removing the relay or would it be ok to disconnect it as it is so I can take it to the shop in order to get the correct replacement?
Cheers
Lazy
P.S - and what are your thoughts on this 5 pin relay only having 4 wires attached plus one spade connection attached to the middle fifth pin, without a wire going into it ?
Edited by lazyitus on Monday 15th January 14:18
Hi Jon,
Peter's right, relays shouldn't rattle, but sometimes the internls come adrift from the outer casing causing a perfectly healthy relay to rattle.
Saying that, it should be a relatively cheap part to replace, so it's a good place to start.
A relay is just a device used for switching different voltages or currents, and could have live wires going to the terminals even if the ignition is off. So unless you know what this relay controls, best dis the battery, you only need to disconnect the positive side.
Don't worry about the spare terminal, it's not unusual to have unused pins.
Good luck,
Derek
Peter's right, relays shouldn't rattle, but sometimes the internls come adrift from the outer casing causing a perfectly healthy relay to rattle.
Saying that, it should be a relatively cheap part to replace, so it's a good place to start.
A relay is just a device used for switching different voltages or currents, and could have live wires going to the terminals even if the ignition is off. So unless you know what this relay controls, best dis the battery, you only need to disconnect the positive side.
Don't worry about the spare terminal, it's not unusual to have unused pins.
Good luck,
Derek
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