![\"IMAG0501\"](\"http:\/\/www.dclabs.lt\/dainiaus\/wp-content\/uploads\/2013\/05\/IMAG0501.jpg\")
<\/a><\/p>\nIt is a very simple circuit.<\/p>\n
The R1, Q1 and R2 are in the front ECU, rest is outside. So, the microprocessor controls the transistor Base via current limiting resistor R1, transistor opens and connects the outside relay to GND. The positive voltage from battery is always supplied to relay. I think R2 acts as a current limiting resistor for transistor\/relai coil circuit. If transistor replaced with BSP76 the resistor may be removed. In fact both resistors are not needed. So, the relay coil magnetizes and switches on its contact. What is connected to that switch it does not matter.<\/p>\n GND for low beam relay is supplied from pin 2 in the Front ECU. Disassembly is easy, just two screws and cap fixation. The transistor, responsible for switching is at position TR8. If you have some other stuff not working and you know that front ECU should control it – this description fits all, only the responsible transistor will be different, so the main thing is to find the right transistor. Simple – take a multimeter, set it to diode check, often multimeter has a beeper in diode check mode. Connect one contact to the right pin (in my case second), and with other just push through the compound to reach the transistor biggest contact (from one side there will be 3 small pins and from another – one big). At the right transistor you will hear a beeeeeep \ud83d\ude42<\/p>\n Quick check showed short circuit between Base and Collector. Couple of seconds of hot air and the transistor is on the table. Now, need to replace it. The transistor has marking:<\/p>\n CB<\/p>\n RG<\/p>\n CB – must be transistor model, R – manufacturer code, G – manufacture date. According to SMD markings book CB is\u00a0BCX68-10<\/a> transistor. R – I think means Siemens. So, I know I can replace the transistor by the same model, but… I don’t have it. I have a smart transistor from the ECU repair (BSP76<\/a>). More details could be found here<\/a>. So, as the polarity of smart transistor is good, I can use it and enjoy all benefits it can provide. The only bad thing is different case. Here you can see the size difference:<\/p>\n Today I noticed, that low beam light in both headlamps is not working. Not good \ud83d\ude42 First checked the Low Beam relay pins. There is 4 pins, two for coil and two for switching +12V to lamps. Connected those pins (one of them has constant battery voltage, other goes to lamps) and lamps shined as…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,4],"tags":[],"class_list":["post-1049","post","type-post","status-publish","format-standard","hentry","category-auto","category-elektronika"],"_links":{"self":[{"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/posts\/1049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/comments?post=1049"}],"version-history":[{"count":14,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/posts\/1049\/revisions"}],"predecessor-version":[{"id":1936,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/posts\/1049\/revisions\/1936"}],"wp:attachment":[{"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/media?parent=1049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/categories?post=1049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dclabs.lt\/dainiaus\/wp-json\/wp\/v2\/tags?post=1049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a><\/p>\n<\/a><\/a><\/p>\n<\/a>But looking at the PCB I thought I might try to fit it in. Here is how I did it:<\/p>\n<\/a>Quite simple indeed, resistors acts as solder pads for 1st and 3rd pins, pin 2 is soldered in its place. Put the PCB into the case, checked in the car, everything is working fine. Final step – add the compound. I used epoxy glue, made a side with a little piece of electrical tape:<\/p>\n<\/a><\/a>Thats it \ud83d\ude42<\/p>\n","protected":false},"excerpt":{"rendered":"