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        General >> Give/Need advice to/from others >> testing a relay
        
(Message started by: ren on Mar 12^th, 2008, 9:06pm)

Title: testing a relay
Post by ren on Mar 12^th, 2008, 9:06pm

can a relay be tested if so how

Title: Re: testing a relay
Post by gozz on Mar 12^th, 2008, 9:30pm

A simple relay is an electromagnetic switch whereby the main circuit is closed by a primary circuit.Many relays have a schematic diagram on them depicting the way round they are connected.If it is just a four pin unit connecting the power to the magnet will produce a click as the solenoid pulls in,the other two pins will now be connected to the appliance,rig up a battery and test light or meter and do circuit tests.If the unit is multi pin you really need a diagram.
GOZZ

Title: Re: testing a relay
Post by TiberiuS on Mar 12^th, 2008, 11:04pm

Yeah, you can check the coil terminals with a multimeter or just put power to the coil and test for continuity accross the contacts. Ideally you want to check that there's no voltage drop accross the contacts, sometimes if the contacts get burnt or dirty you get a voltage drop which creates heat which kills the relay and causes problems elsewhere because the voltage is lower than it should be.

If it's an intermittent fault you're chasing then don't bother, just drop in another relay. Sometimes they go bad like that and you'll tear your hair out trying to find the fault.

Title: Re: testing a relay
Post by jonnycab on Mar 12^th, 2008, 11:16pm

Or a quick trip down the breakers & walking out empty handed....apart from a pocket full of relays....is a cheap, non technical option ;)

Title: Re: testing a relay
Post by ren on Mar 12^th, 2008, 11:41pm

a forum member as sent me one, but its
giveing me the same as my own,thats why
i asked about if they can be tested.

Title: Re: testing a relay
Post by jonnycab on Mar 13^th, 2008, 12:06am

What relay is it that you're having trouble with Ren ?

Title: Re: testing a relay
Post by ren on Mar 13^th, 2008, 3:06pm

front heated screen relay R18
the control light in the switch doesnt illuminate
have replaced the fuses
have replaced the switch
and changed the relay still no illumination of switch

Title: Re: testing a relay
Post by peteHull on Mar 13^th, 2008, 3:28pm

on 03/12/08 at 23:16:18, jonnycab wrote:

Or a quick trip down the breakers & walking out empty handed....apart from a pocket full of relays....is a cheap, non technical option ;)

JC you know there is no one on this forum who would dream of doing such a thing..... That would be naughty >:( I am surprised at you.....

;D

Pete

Title: Re: testing a relay
Post by gozz on Mar 13^th, 2008, 11:02pm

ren.
Is the heated screen heating,can you hear the relay when you press the switch ?
The switch lamp failing to illuminate is common,and need'nt mean failure of the system.
jonnycab.
Your local nosey inspectorate of scrapyard pocketers is on to you !
GOZZ.

Title: Re: testing a relay
Post by Snoopy on Mar 14^th, 2008, 7:59am

Check the earth straps either side of the front screen, they are open to the elements and suffer from oxidisation .

Title: Re: testing a relay
Post by jonnycab on Mar 14^th, 2008, 11:46am

"Or a quick trip down the breakers & walking out empty handed....apart from a pocket full of relays....is a cheap, non technical option".......

Sorry about that, I don't know what I was thinking..... I certainly wouldn't dream of doing anything like that....honest ;)...... :)

Title: Re: testing a relay
Post by ren on Mar 14^th, 2008, 9:36pm

Snoopy
Where are the straps located,you say either
side of screen,is there a pic showing the location.

Title: Re: testing a relay
Post by Simmo on Mar 15^th, 2008, 6:17am

Have a look at THIS page (http://www.fordscorpio.co.uk/manual/body/trim/grillecowl.pdf). You need to remove this grille in order to access the connectors. If you look at the third picture the connection is just about where the left hand arrow is pointing. There is another one on the opposite side. ;)

Title: Re: testing a relay
Post by ren on Mar 15^th, 2008, 9:06am

Simmo
Thanks for the info,wasnt sure if i had to
remove the rubber seal to get to them, so
happy i havnt,will have a look tommorow.

Title: Re: testing a relay
Post by Snoopy on Mar 15^th, 2008, 9:31am

Ren they should be visible without removing any trim ..... MINE are. I will post a picture later if it helps ...

they should be located either side of the widscreen .. visible when the front bonnet ( hood ) is lifted ..

Title: Re: testing a relay
Post by Tompion on Mar 16^th, 2008, 1:02am

My car only has connectors for the feeds visible, no connectors for the earths – just earth wires. I assume my earth connectors are at the top of the screen as shown here:
http://www.fordscorpio.co.uk/manual/windows/windscreen.pdf

Title: Re: testing a relay
Post by ren on Mar 16^th, 2008, 12:32pm

yes i could only locate the feed connectors
so i cleaned them up and now have illumination
of the switch,got to wait now for a frosty morning
to see if the screen heater works.
Snoopy thanks for pointing me towards the connectors.
Thanks for all the replys everyone
ren