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There is already a 12V feed in the door.

The power for the cigar lighter.

Lars

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I've just rebuilt the door frames on my 1990 Esprit so I thought while I'm in the I'd do this mod. So, relays purchased and wiring diagram here followed. To continue my usual success with car wiring it doesn't work :angry:

New perm live from fuse box checked and OK

When I move the window switch one way one relay clicks, and the other way the other relay clicks. Good. Problem is that nothing happens at the motor (which I know is OK and works if you connect direct to 12v).

I also notice that the switched live output on BOTH relays energises no matter which relay is pulled in by the window switch.

What seems to be the case is that of the 2 wires from the motor, one is live and one earth, reversing depending on whether window is going up or down. Similar to the Excel situation mentioned earlier in this thread.

Is there an easy solution to this or will the mod simply not work on my car?


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you need to get a multimeter on it and see what you are getting voltwise on the feed into the relay and the feed out.....

it will work on your car - once it's wired correctly


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I'll try and document what I did on the Excel, but in essence (should anybody feel like reverse engineering it), rather than having a change-over relay for up and a change-over relay for down, it's a change-over relay for one motor wire, and another for the other motor wire. One of the relay throws on each goes to earth, and the other throw on each to the +12v source.

The solution, puts either +12v & 0v, or 0v & +12v to the motor wires as appropriate when a switch is activated, 0v & 0v when no switch activated, and even if a relay fails in the "on" position you just get +12v &+12v which doesn't cause a problem (fail safe). 

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Andy, sorry if I'm a complete wiring numpty but can you draw out the wiring diagram for what you did? Sounds like what I need to do. Is a 'changeover' relay easy to find? I guess I'll need 4?

 

Barry, thanks for the advice. I do have 12v going in and coming out of the relays, the problem is one should be feeding earth to the motor. Then they need to reverse when the window switch is flipped the other way.

Why is nothing ever simple....!

 


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Are they double pole relays you are using??

this isn't hard - post up some pictures and  it will be easily solved. 

The window motors are just two wire aren't they ??? 

image.png

this is what you should have


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Fab Barry, thanks! This is completely different to the original diagram in the post and what I've just created...

My relays are just 4 pin so I guess I'll need different ones.

Where does my new direct from fuse box 12v feed go to? Should I use it to feed the first relay, leaving the original 12v just on the switch? Or do I not need it at all..?

Thanks Andy too!


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The issue with the old esprit switches is they aren't rated at the current the motors draw. Over time they degrade and you get voltage drop across the switch - and then this manifests in slow opening.

those relays are also are also effectively 4 pin as 87a and 85 are hardwiring together.

you don't necessarily need a new 12v feed - as there should already be one at the switch. 


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So can I use the 4 pin relays I already have then? Sorry if that a really stupid question but I'm out of my depth in terms of automotive wiring here!

Given that the mod was originally designed for an older Esprit am I likely to see any benefit on my car by adding the relays? I'm assuming that having a more direct 12v feed rather than through the switch will still be better.


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Post a picture of the relay part numbers you have.

the switches on the doors are "crap" for the purpose they are used for. By cutting a relay in the current demand through the switch is just to energise the coil in the relay which is negligible.

my 1991 had the same setup and I never got round to doing this - and it needed it done really. 

Happy to sketch you a picture for your relays you have


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Thanks Barry!

I'll get a pic tomorrow. They're just normal 4 pin relays.


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image.jpeg

the relays are no good - you need both no (normally open) and nc (normally closed) connections

87 and 87a normally I believe 


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On 4/30/2016 at 11:23, Barrykearley said:

image.jpeg

the relays are no good - you need both no (normally open) and nc (normally closed) connections

87 and 87a normally I believe 

OK so I'm officially confused! This relay diag looks like the ones I already have.

I think what I need are these, wired as shown in your earlier post above?

numbers-of-a-relay.jpg


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That's correct. The image that Barry posted, and you've quoted, is the image of the relays you have. Yes, what you want is a pair of relays that have pins 87 and 87a, and here's the diagram of those.

 

5-pin-relay.gif

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Car_Relay_12V_30A_5Pin_Changeover2.jpg

What he said.....!!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Thanks guys (and Barry)! I'll order up the right relays this week.

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New relays arrived today. Wired as per Barry's diagram and all working OK now.

Thanks guys!

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I think so yes.

The seals are all now so still bedding in and I was testing without the car running. Still seemed to go up and down at a respectable speed though!


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