j_jza80 Posted October 27, 2015 Share Posted October 27, 2015 (edited) ================================================================================================================================================================================================================================================================================================== Problem solved. full guide to fitting heated seats here: http://www.mkivsupra.net/vbb/showthread.php?330119-How-to-Guide-Install-heated-seats-using-the-OEM-heated-seat-switch&p=4108429#post4108429 ================================================================================================================================================================================================================================================================================================== I'm trying to get to the bottom of why my heated seat switch won't work, which is becoming pretty infuriating! When I tried a new switch the other day, the dash illumination fuse blew straight away. According to the little information I can find on this subject, the heated seat switch pinout is as follows: 1: ground 2: power to LH seat heater (when button pressed) 3: illumination negative 4: main power in 5: illumination power 6: power to RH seat heater (when button pressed) (see thread: http://www.supraforums.com/forum/showthread.php?661737-Aftermarket-seat-heater-with-oem-switch ) However, wiring the switch like this deems to produce sporadic results. It has blown a couple of fuses, and junked a dash dimmer switch. And the illumination seems inconsistent. i've just tried a different switch which I tested with a makeshift rig, and it actually made one of the PCB connections pop! So, I've stripped down the switch, and this is the layout of the circuit board: TOP BOTTOM Please excuse the basic diagrams! So, straight away to me, it looks like pins 2 & 4 are for the button illumination, not 3 & 5 as per the pinout on Supra forums. The LEDs at the top end of the board indicate when each seat circuit is activated, so they must each connect to the main power input pin, and each seat power output. I would appreciate it if anyone with more knowledge of PCBs could have a look at this for me, and save me a lot of time and heartache! Thanks. Edited January 16, 2016 by j_jza80 (see edit history) Quote Link to comment Share on other sites More sharing options...
ripped_fear Posted October 27, 2015 Share Posted October 27, 2015 Will be keeping an eye on this as I want my UK's wired in properly at some point. Have the seats and switch but no wiring. Quote Link to comment Share on other sites More sharing options...
Iky Posted October 27, 2015 Share Posted October 27, 2015 I retrofitted heated seats into mine using the factory switch but cant for the life in me remember the pinouts. I will see if I still have some notes or doodles. I did do most of it from the workshop manual though. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 27, 2015 Author Share Posted October 27, 2015 That's why I'm looking for a UK spec owner would be easy enough testing the outputs with a test light. If you can find anything, that would be great. Did you use relays for each seat? Quote Link to comment Share on other sites More sharing options...
Iky Posted October 27, 2015 Share Posted October 27, 2015 can I ask, did it used to work before? - - - Updated - - - That's why I'm looking for a UK spec owner would be easy enough testing the outputs with a test light. If you can find anything, that would be great. Did you use relays for each seat? Yes, two relays. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 27, 2015 Author Share Posted October 27, 2015 (edited) The guy on Supra forums didn't, but I wonder if maybe the draw from my kit is too much for the switch to handle? No, it's not worked. It all works perfectly until you try wiring it through the factory switch. Edited October 27, 2015 by j_jza80 (see edit history) Quote Link to comment Share on other sites More sharing options...
Iky Posted October 27, 2015 Share Posted October 27, 2015 Probably worth mentioning, I've not actually tried mine on the elements yet. But i have had the output wired up to an audio amplifier to test. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 27, 2015 Author Share Posted October 27, 2015 How come you've not wired it up? Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted October 27, 2015 Share Posted October 27, 2015 (edited) J, have you tried giving Andy Blyth a pm? He is sh1t hot on stuff like this http://www.mkivsupra.net/vbb/member.php?18063-Andy-Blyth Edited October 27, 2015 by Frank Bullitt (see edit history) Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 27, 2015 Author Share Posted October 27, 2015 Great, cheers mate Quote Link to comment Share on other sites More sharing options...
Scott Posted October 27, 2015 Share Posted October 27, 2015 Looks to me like you have 1-6 in the wrong order. Could be wrong though. No.4 being the power in only makes sense on your pin "3" looking at the board from "underneath". Quote Link to comment Share on other sites More sharing options...
Guest Sketch Posted October 30, 2015 Share Posted October 30, 2015 On your Switch: 1. POWER OUT (SEAT 1) 2. ILLUMINATION 3. POWER IN (SWITCHES) 4. ILLUMINATION 5. POWER OUT (SEAT 2) 6. LEDS (COMMON) - 1,3,5 should be thicker wires IF it is a +12v switch - if they are the same size as the others it probably runs through relays (Neg Trigger) - 2 OR 4 will be a WHITE/GREEN which is ILLUM Negative - the other will be +12V with lights on - 6 is PROBABLY a negative, but only if pin 3 is a +12v IGN. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 (edited) Thanks I don't have the factory loom to look at for reference though. Your pinout makes more sense looking at the pcb Edited October 30, 2015 by j_jza80 (see edit history) Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 Also, I'll really need to run 3 relays then. 1 on the main power in to the switch, so it can only be used when the ignition is on, and 1 for each seat. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2015 Share Posted October 30, 2015 Have you blocked me Jay? I told you your circuit was reversed lol. 1-6 the wrong way around Quote Link to comment Share on other sites More sharing options...
Guest Sketch Posted October 30, 2015 Share Posted October 30, 2015 Realistically, the heated seats in mine (which are LS400) only draw about 3-3.5A when on. So each could be run from a 15a feed or even a 20a feed to power BOTH relays. You don't need to use a relay on the Ignition circuit because it is only going to be switching relays therefore doesn't draw any significant current. So you are retrofitting heated seats is that correct? Do you want a loom diagram done? JV Quote Link to comment Share on other sites More sharing options...
Guest Sketch Posted October 30, 2015 Share Posted October 30, 2015 Also what Scott says makes perfect sense - then 3 and 5 would be illumination matching the diagrams you've found on here. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 Have you blocked me Jay? i told you your circuit was reversed lol. 1-6 the wrong way around Sorry, reading that back it does read like I was directly addressing sketch, but I meant it for you too I really appreciate the input Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 Realistically, the heated seats in mine (which are LS400) only draw about 3-3.5A when on. So each could be run from a 15a feed or even a 20a feed to power BOTH relays. You don't need to use a relay on the Ignition circuit because it is only going to be switching relays therefore doesn't draw any significant current. So you are retrofitting heated seats is that correct? Do you want a loom diagram done? JV So run the ignition live into the main feed of the switch, then use the outputs to switch the relays both the seat feeds?. That makes sense. Yes, I'm retrofitting it. Quote Link to comment Share on other sites More sharing options...
Guest Sketch Posted October 30, 2015 Share Posted October 30, 2015 Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 Thanks Is it necessary to run the feeds for the relays/seats from the switched ignition live though? Surely using relays means they can, and should come straight from the battery/fusebox? And also, the illumination has to be earthed back through the illumination ground circuit, or the dash dimmer won't work. Quote Link to comment Share on other sites More sharing options...
Guest Sketch Posted October 30, 2015 Share Posted October 30, 2015 Illumination - Correct sorry yes it'll ground through any White/Green wire (dimmer circuit) - easiest is to take that feed from the light on the Cigar lighter. Yes you can take the 15a fused feeds to pin 30 on both relays from B+ at the fusebox, it doesn't really matter - the purpose of the relay is to allow a low current circuit ie switch to turn on/off a higher current circuit regardless of where the higher power circuit comes from. Hope this has been helpful and good luck! Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted October 30, 2015 Author Share Posted October 30, 2015 Illumination - Correct sorry yes it'll ground through any White/Green wire (dimmer circuit) - easiest is to take that feed from the light on the Cigar lighter. Yes you can take the 15a fused feeds to pin 30 on both relays from B+ at the fusebox, it doesn't really matter - the purpose of the relay is to allow a low current circuit ie switch to turn on/off a higher current circuit regardless of where the higher power circuit comes from. Hope this has been helpful and good luck! It has been very helpful, thank you I'll be working on the premise that the pinout is backwards, and changing the current single relay for the twin as discussed. I'll post up my results, and post up an amended diagram for future reference Quote Link to comment Share on other sites More sharing options...
Iky Posted November 1, 2015 Share Posted November 1, 2015 Sorry J, I could not find anything. Next time i have the dash panel off ill try to remember to take a photo. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.