Lorenfb

And for those that got a headache from this thread, they can order a completely
rebuilt unit from 928 Int'l at a reasonable price.

69gaugeman

Docmirror,
I just went by the spec sheet. All relays wear out. How long did the originalone last? I would suspect that just replacing the relay would give you somewhere close to the original life (maybe slightly less as other components resistance goes up it might draw some extra current).

dr bob

Problem with the original is that its amp rating is for AC, and that rating is less than half of what the clutch coil actually draws. So maybe there is some over-engineering in there for the extra current. But there's still the inductive kick when the relay opens and the clutch coil magnetic field collapses. This is the same effect that makes ignition coils work so well, by the way. You get a pretty nasty arc across the relay contacts every time it opens.

My solution was to mount a 10A DPDT relay on the outside of the case, using some double-sided tape. Short wire jumpers are used to connect the old circuit board points to the new relay. Results: It works perfectly every time, and no worries about getting stuck again with intermittent or no AC compressor function.

If you do insist on using the underrated relay (anything less than 6A DC rating....), at least put in a suppressor diode across the coil contact on the relay, so the coil can drain through the diode instead of arcing across the contact. That will extend the life somewhat.

SharkSkin

While that may be true and not such a big deal on the later cars, IMHO it's worth it to have a second relay bear the brunt of the load, especially if it's easier to get to. How many times do you suppose you can re-solder on that 20 year old PCB before traces start to lift? Especially if one is not used to soldering PCBs...