Can someone please help me troubleshoot the diode that feeds the K1 relay in the fusebox of my '91 318is? My auxiliary fan will not come on when I push the a/c snowflake button. I can jump the K1 and K6 relays and get the fan to turn on low or high speed, but it will not run with the a/c button depressed. The ac button lights up, but I get no voltage into pin 86 of the K1 relay. The simplest answer sounds like the diode in the fusebox, but I am having a hard time getting to it. I can remove the three philips head screws that hold the upper fusebox tray to the lower section, and I can see the circuit boards underneath, but there is a lot of resistance to pulling the upper tray up sufficiently to get access to the underside. Before I break something, is there another fastener, or is this inflexible 30-year old wiring?
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I found it. A little more cajoling revealed the diode, and it was indeed dead. -
Does anyone know the part # for this diode? I can't find it on realoem.Comment
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Fantastic, thanks!Comment
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What did you end up doing to pop off the top to expose the top of the circuit board?Originally posted by idickers View PostComment
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It turns out that the diode is below the circuit board, so I did not need to separate the circuit board from the top of the fuse box. I was having trouble getting the top (with attached circuit board) raised high enough from the bottom of the fuse box to get at the wiring.Comment
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Okay, the mystery continues. I now have a known good diode, and good relays. I can still trigger the high and low speed fan if I jump the K1 or K6 relays. I can trigger the high speed fan if I jump the temp switch on the radiator, but cannot trigger the low speed fan from either the temp switch on the rad or the a/c snowflake button (which lights up when depressed). I can ring the radiator temp sensor plug for continuity to the relay, so the wiring seems to be intact. Any suggestions where to look next?Comment
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Are you sure you installed the diode in the correct direction?
There is not much to the cct.
2001 silver/Blk 325 cabby. SOLDOriginally posted by codyep3
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Yes. The diode was marked, and it had male & female connectors, so there was only one way to install the diode.Comment
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