Evening folks. Ford stopped making this particular relay, so RS owners with dead ones are at the mercy of finding one for sale - Last one I saw was 160 quid, which is hilarious, but also rather unfortunate. I don't know what causes their death, because mine still works. However, no one else has taken one apart to work out what's gone wrong with the damned things when they die that anyone in the owners club knows about. Fingers crossed I get a dead one soon and can work it out, however. On the quite high chance that I can't, I could do with a hand IDing components - And I was hopeful some of you electrical whizz types might be able to shed some light. Here I'm seeing two diodes and two caps, but I don't know how to work out what the diodes are - I can only see '47' and '04' from the angles I have - I can see there's more there, but without desoldering them I'm not sure if that's enough to ID them. The underside is a bit more problematic. The things with three poles, I think, are transistors - But I have no idea whether the numbers stamped into the tops is helpful in IDing them. The others I'm guessing are caps or fuses? Is there any sure fire way to tell with it all assembled? I don't know what that little thing on the right is, the printing on it is '027P', does that help work it out? My gut feeling is that the caps have leaked or something - 15 years or more in an engine bay with nothing but a fuse box for protection from the heat, and I'm betting they've not fared well. I may also have some interest in possibly getting a board designed so if the pins and what I figure is an electro magnet can be found then "new" ones can be made. Perhaps with a little more finesse than the now nearly twenty year old Ford design. But fixing broken ones would be a start.
No expert but it looks like a resistor of some flavour [if i'm looking at the right 'little thing on the right'] Do you not have a multimeter you can prod it with?
I do indeed - Stabbing it as shown produced.. Odd results. It started at 4.78, slowly dropping to 3.9, between that and taking a picture it crept back up again. FWIW: I found what I stabbed out with the last time I looked; 223 - 22k Ohm 103 - 10k Ohm 104 - 100k Ohm 183 - 18k Ohm 273 - 27k Ohm 473 - 47k Ohm 824 - 82k Ohm 101 - 100 Ohm 1001 - 1k Ohm 2403 - 240k Ohm 102 - 1k Ohm 000 - ??? 1Fp 26 2x 3Fp 21 FF 7 Didn't fancy colouring peoples thoughts on what the bottom stuff is with my "I barely know what I'm doing" multimeter usage.
Should be a very easy fix if you know what the parts are. 9 times out of 10 though you just need to reflow the solder and replace the large caps. Might be worth a shot sending this guy a message and see if he can ID the parts.
To the best of my googling they are - https://www.nexperia.com/products/b.../single-bipolar-transistors-100-v/BC847B.html and https://www.nexperia.com/products/b.../single-bipolar-transistors-100-v/BC857B.html respectively EDIT is... this? again to the best of my google-fu ability https://www.nexperia.com/products/b...transistors/darlington-transistors/BCV27.html EDIT 2 - google fu tells me that's a 0-ohm jumper EDIT 3 - this should help with the codes on the SMD resistors, though your prodding seems to be on the money there - https://www.hobby-hour.com/electronics/smdcalc.php
No need to poke those: that's what the numbers mean. 103 = "10" and "3 zeroes" = 10,000 Ohms = 10k. 104 = "10" and "4 zeroes" = 100,000 Ohms = 100k. 183 = "18" and "3 zeroes" = 18,000 Ohms = 18k. 273 = "27" and "3 zeroes" = 27,000 Ohms = 27k. And so on, and so forth. 000, meanwhile, is "00" and "0 zeroes" = 0 Ohms. It's a zero-ohm resistor - a wire link, basically. You could replace it with a bit of wire and everything'd work fine. EDIT: Pfft, didn't scroll down far enough to see @RedFlames had beaten me to the punch!
it could be a capacitor [which would make sense given it's next to 2 other caps]... and the 027P being the μ-farad rating? though wither it's 0.27μF or 27μF... idk It seems to go 470μF -> 47μF -> ?? so if it is a 27μF @ 25V, 105°C [based on the other 2 caps], then you're looking at this https://uk.farnell.com/wurth-elektronik/860160472004/aluminium-electrolytic-capacitor/dp/3235569 the 0.27 and 2.7 ones i can find are all SMD ceramic caps so i'm guessing it's 27 if it is indeed a cap
could be, and i bow to your superior knowledge here mu mind went to μ bc that was what was on the neighbouring ones...
I knew there was a reason I asked here. Thanks gents! What I can't quite understand is why there's so much complexity in this relay. It's the main fan relay, and is meant to come on at 112c - which is read by the temp sensor in the head, so why it wasn't a simple trigger like the other relays appear to be, I'll never quite understand.
hysteresis? maybe? so it comes on immediately at 112C but stays on for a little while if it drops under again. [i have no idea]
Possibly - I'm not the best person to know, one of my first mods was a thicker radiator and a temp sensor on the inlet to said radiator, as well as a lower temperature thermostat, so mine only ever got to 112 when I was sat in traffic - A bit of wind through the rad and it stayed cool enough that I never noticed the fan running anywhere else - And it is one loud fan. I figure that the relay is energized when it hits 112 and power removed some time after it goes back under a lower threshold, but the ECU's are encrypted and while enough sense has been made to tune the damned things by some places, a lot of that information isn't readily available. What gets my goat is that this relay seems to only be on the RS, and not on any of the other Focus range - Which makes it an absolute sod to find (I've had a thread asking for one for over a year), and they almost never appear on ebay. It's a frustrating problem to solve! And more over, since I'm going down the route of EV'ing mine, I don't even have the means to test it properly, so any attempts I make will have to go over to the nearest guy I know with one (He has four..) to test. Right old palava really, but I said I'd try if I ever got my hands on a dead one, so.
I'd say so, yes, very much appreciated! I like electronics, but I never find the time to sit down and learn enough about this stuff to not be in a 'mymatevince' situation where I need to test a broken one and a working one to work out what's shagged.
Its a diode (might be a zenner, but i doubt it), if its placed in parallel with relay coil then its used as a flyback diode. Most likely the case, not much else there to go wrong
Actually, I reckon it's a thermistor. Check this out: Look familiar? Easy enough to test: @liratheal, turn your multimeter to resistance measurement, stick it on the leads, and measure resistance. Then hold the body in your fingers for a bit to warm it up, see if the resistance changes. If it does, that there's a thermistor. If not, see if you get near-zero resistance in one direction and infinite resistance in the other: if you do, 's a diode and I'm wronger than a wrong thing. EDIT: Nope, I'm wronger than a wrong thing. That site's just stolen an image of a Zener diode and flipped it horizontally. @Xlog's right: 's a diode.
Image is for illustrative purposes only. Even on the likes of CPC/Farnell you can't [reliably] go off the images.
Yep, couldn't really make it out on my phone, but if it's in a clear casing it's usually a diode. As for the rating, I haven't looked at those in years, so can't help there.
First thoughts would be to replace it with any old relay, but then you reckon the RS lot must know something I don't so there must be a reason for that. Whether it's to keep some complex ECU happy or because they like to keep their cars mint, who knows? Is there much chat on the subject on the RS boards? Nothing came up on my 30 seconds of trying
