Wiring help for relay

Post by **beebee** » Sat Dec 13, 2003 10:50 pm

I have attached a wiring diagram for my ac and ventilation. The symptom is that I my fan doesn't work. The fan resistor isn't getting power and when you switch the AC button on in the dash it doesn't light up like it used to. After cheching my manual, I think it is either the controller in the dash or the heater relay. How do you check a relay? Should there only be one live terminal? At the moment, one side of the coil is live when the iggnition is on but there is no current at any other of the terminals even when the air is switched on in the dash controller. Does that mean that the dash controller is the trigger for the relay and it's not telling the relay to switch? Or should the relay have a current on the low voltage side anyway? Any help appreciated.

Hope the attachment works

Post by **beebee** » Sat Dec 13, 2003 10:51 pm

Attachment is coming - just a few minor difficulties.

Post by **beebee** » Sat Dec 13, 2003 11:03 pm

Post by **ozy1** » Sun Dec 14, 2003 9:57 am

When it comes to relays, you will always have one live wire. When you flick the switch for the relay, you will then get 2 live wires, unless, your relay has given up the ghost.

as for the problem, if the swtich wire goes through the controller you may have a faulty controller, yet again, you may have a faulty relay.

I took a look at the diagram, but due to resizing i cant read it very well.

Shawn

hope this helps

Post by **beebee** » Sun Dec 14, 2003 1:14 pm

ozy1 wrote:When it comes to relays, you will always have one live wire. When you flick the switch for the relay, you will then get 2 live wires, unless, your relay has given up the ghost.

as for the problem, if the swtich wire goes through the controller you may have a faulty controller, yet again, you may have a faulty relay.

I took a look at the diagram, but due to resizing i cant read it very well.

Shawn

hope this helps

Wouldn't you get 3 live wires once the relay is tripped?

Low current in
High current out
Trigger wire

Post by **ozy1** » Sun Dec 14, 2003 2:29 pm

sorry, indeed your correct,

you will have 3 live wires

Post by **beebee** » Sun Dec 14, 2003 5:21 pm

ozy1 wrote:sorry, indeed your correct,

you will have 3 live wires

Still

Post by **ozy1** » Sun Dec 14, 2003 5:49 pm

is there any chance of gettin a clearer diagram?
that would help a bit,

if you do, you can email it to me and ill take a look,

shawn_waid@hotmail.com

Post by **ozy1** » Sun Dec 14, 2003 5:57 pm

buy having a look at the diagram, i would say that there is a possibility of a faulty switch, or a damaged trigger wire, with out either of there you will get no power to activate the relay. which in turn wont run the fan.

Shawn,

P.S -: a clearer diagram will still help for a better look.

Post by **beebee** » Sun Dec 14, 2003 6:55 pm

I'll go and rescan a clearer diagram - thanks for the help

Post by **ozy1** » Sun Dec 14, 2003 6:56 pm

more than welcome!

Post by **beebee** » Sun Dec 14, 2003 7:13 pm

ozy1 - you have mail!

Post by **ozy1** » Sun Dec 14, 2003 9:34 pm

okay, taking a look at the diagram,

i would assume you have checked the all the fuses involved in the operation of the AC,

one question, with a multimeter, have you, or could you check to make sure you have power across the fuse terminals,

there would be 2 other things i would check, try and manually switch your heater relay by unpluggin it from the system, then adding 12 volts to the switchin terminal, then find out if you have a circuit acroos 2 of the other terminals (your power in and power out termials)

also, you ventilation switch is a slide switch i take it, you may have broken contacts there.

also, when you turn on the AC switch does it run without the light, or not at all?

Post by **beebee** » Sun Dec 14, 2003 10:26 pm

ozy1 wrote:okay, taking a look at the diagram,

i would assume you have checked the all the fuses involved in the operation of the AC,

one question, with a multimeter, have you, or could you check to make sure you have power across the fuse terminals,

there would be 2 other things i would check, try and manually switch your heater relay by unpluggin it from the system, then adding 12 volts to the switchin terminal, then find out if you have a circuit acroos 2 of the other terminals (your power in and power out termials)

also, you ventilation switch is a slide switch i take it, you may have broken contacts there.

also, when you turn on the AC switch does it run without the light, or not at all?

Yes I have checked all fuses

Haven't cheched for current across fuses but will tomorrow night

So by providing 12V to the switching terminal, I should detect current on the power in and power out terminals - correct? I would have thought that to obtain a current at the power out, you would need current at the power in as well as the switch.

Yes I may have damaged the contacts - unlikely for all to go at once and without notice I'd think

For the AC to run, the button needs to be depressed and the slide swich on positions 1,2,3 ie not low
At the moment nothing happens with the swith in any location. The AC light on the button doesn't even come on

If I can confirm that the heater relay is operational then the fault will either be a broken wire or the slide switch on the dash.......I think

Post by **ozy1** » Sun Dec 14, 2003 10:33 pm

So by providing 12V to the switching terminal, I should detect current on the power in and power out terminals - correct? I would have thought that to obtain a current at the power out, you would need current at the power in as well as the switch.

if you provide power to the switchin terminal, you should be able to feel/hear the relay switch, now, if you have a decent multimeter you will have a resistance setting, if the relay is switching, and you check for resistance across the power in and out terminals, it will read a figure, but if it doesnt, it will read O/L which tells you, you have an open circuit, this will mainly let you know if you have a broken contact in the relay.

Post by **beebee** » Sun Dec 14, 2003 10:39 pm

Shall do tomorrow - thanks for the help

Post by **ozy1** » Sun Dec 14, 2003 10:40 pm

more than welcome mate

Post by **beebee** » Mon Dec 15, 2003 9:08 pm

Ok I had very little time this afternoon but I did drop into the wreckers to get something for my mother's car and while I was there, I grabbed another heater relay. Then I went straight out to the carpark, plugged it in and still no go. So as far as I'm concerned, it's not the relay. So that's one possiblility off the list and I'll cancell some more out next time I get a spare 5 mins. Thanks for the help once again

Post by **ORSM45** » Tue Dec 16, 2003 6:12 pm

just bypass all the other switches by 'hotwiring' the relay and see if there is voltage at the fan using a multimeter.
if there is then your problem is down the line a bit more. continue process until the fan doesnt have voltage. then thats your problem.

Post by **beebee** » Tue Dec 16, 2003 8:24 pm

So by bypassing the relay, although there won't be enough current to run the fan, I should be able to detect voltage - I see

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Wiring help for relay

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