Following the fate of every MR2 owner, my PS relay is playing up (I didn't run diagnostics cos I'm not sure which pin is Tc yet but it's prob the relay) so I bought one from Jaycar. Unfortunately they didn't have 50A-70A with 4 pins but the 5 pin so I bought that one instead. Because it has 5 pins, I'm sure which ones I'm supposed to connect to, or if it's even compatible (I assumed I could work around it).
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

I know the two smaller wires connect to the ones on the side 85,86 (does it matter which end goes where?)
Then the two bigger ones should be 30 and 87/87A. I'm hopeless with electrical language but I'm guessing it's supposed to toggle on and off between 87 and 87A. But since we only have 2 big wires to connect with, which one should it be?
 

I'd honestly ditch the old mechanical relay and move to a Solid State Relay (SSR). You can buy them from Jaycar for like $50 and they take some abuse (I've run 37v 100A loads through some).
 
http://www.jaycar.com.au/productView.asp?ID=SY4086
 

Tree
Following the fate of every MR2 owner, my PS relay is playing up (I didn't run diagnostics cos I'm not sure which pin is Tc yet but it's prob the relay) so I bought one from Jaycar. Unfortunately they didn't have 50A-70A with 4 pins but the 5 pin so I bought that one instead. Because it has 5 pins, I'm sure which ones I'm supposed to connect to, or if it's even compatible (I assumed I could work around it).
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

I know the two smaller wires connect to the ones on the side 85,86 (does it matter which end goes where?)
Then the two bigger ones should be 30 and 87/87A. I'm hopeless with electrical language but I'm guessing it's supposed to toggle on and off between 87 and 87A. But since we only have 2 big wires to connect with, which one should it be?
 

Do you have a multimeter? If not you should own one for doing this type of work on the car.
The two connections 85 & 86 are for the relays coil. Hook up the smaller wires to these. Shouldn't matter which way around they are.
for the large wires, put one of them on pin 30 and the other on 87. 87a should be the normally closed contact where 87 looks to be normally open. You can confirm this with a multimeter. 

Better solution is to ditch power steering.
 
My NA has a gutted power steering rack and there is very little difference between it and the fully working power steering in my turbo.

I 100% agree with ^Knightrous, I have also upgraded & run a 100amp SSR from J-Car, since the upgrade never once had it drop out or fail to activate. Fully recommend the upgrade to anyone with an early SW20 w' powersteering.  In saying that my later model gen 3 is still operating fine with original PS relay - (Touch wood).

I used the $40 Ford replacement you can get anywhere.

Well here's the thing guys...the relay cost me $9 lol. I like the idea of solid state but $50 is too much for this POS!!! (nek minute car breaks down forever). I think the PS only dies on hot days, past few days have been kind to me.
 
Also I plan to sell the car with good resell value thanks very much Iain. And also one handed drifts FTW! Do you even lift is probably yes for you because dead PS on my car is bloody horrible. Oh yeh dude I found RSR Race springs >:D
 
Thanks skylighter I'll defs give this a shot. With the original relay is it always normally open? Anyone in this day and age without a multimeter should just be electrocuted. By an electrician.
 
If I could get the $40 Ford replacement from ANYWHERE, how come Jaycar didn't have it? Huh? How you explain this to me Mr Webb? lol
 
Hmm what the hell did they put in my dinner...

You been on the chilli burgers again Tree? Back in ye olde times when i had a working MR2 (circa 6 years ago....) it was 2 years before THAT when i replaced it with the Ford item. Back then you could buy them everywhere....... then again some people still probably had dial up internet back then too.

Haha perhaps I'm training for next year's challenge, burger that is....
Ended up getting the relay fitted took longer than I thought cos I'm just slow. Forgot to unplug the batt thinking "how could I get this wrong pssst" and nek minute sparks flew LOL lesson leart there...then friend saw the glue (that sticks the prongs to the relay) and some reason thought it was due to the arcing and we all panicked. Then I was like that's weird relays don't blow up (do they?) and finished the job.
Looking back 90% of the time was unproductive lol

Ha ha. 
 
At least it wasnt a spanner between an alternator main power and a fuel rail, because that results in more then 90% un-productive time!
 
I think we should set a challenge that anyone that finishes the burger scores free entry to next years track day.