hd keeps destroying head units

Hi guys, I've been reading contributions to this forum on and off for years but have only just signed up. My partner has a Harley Davidson 2011 Street Glide, which he lets me ride and it has been a fantastic bike in all but one respect: the sound system has hardly ever worked. The first head unit died several months ago and it took a long while to get the bike back to the shop (we live in the outback) and get a new one fitted. Shortly after the replacement one was fitted it also died. No display, no signs of life. Now Harley Davidson have been ignoring the dealer who is trying to do something about it. My partner now thinks he should get an aftermarket unit but I've been insisting it must be the bike, not the stereo, because the odds of 2 dodgy head units in a row is pretty slim. So my question: is it plausible that the electrics in the bike are doing something to the head units to cause them to fry? If so, do you know what I should check?

Voltage. It should never exceed 16V for most electronics, maybe lower for some (eg, 15.5V). And it should never exceed 14.4V (long term) at the battery terminals (for the sake of the battery). But also ensure the HU is properly earthed (grounded for you others) and that there are good earths overall. (Bad earths can raise voltages, cause alternate paths to blow circuits, and generally blow things through intermittent contacts.)

Thanks, I never even thought of the earths. It would make sense that there might be an earth that isn't fastened properly on the bike somewhere.

Of course in the shower this morning I thought of speaker connections and impedances etc, but I assume they are matched etc, ad they are unlikely to cause a dead unit - just dead output. Also any intermittent link - fuses, connectors etc. And the usual tricks - disconnect & reconnect all connectors; rotate (else swap) all same sized fuses, etc. It intrigues me if HD are distancing themselves IF the unit is a standard feature. If not, fair enough (maybe...).

Thanks again for your help oldspark and I have an update in case anyone out there has the same problem. We also thought it was a bit strange because, yes the head unit is a standard Harley Davidson one (manufactured by Harman Kardon), and the claim is through the dealership under warranty. Well my fella took it for a lovely 380 mile ride back to the dealer again and at least we got a partial answer. The head unit itself is fine! The ECM had lost memory of it and cut the power to it making it appear completely dead. The dealer reset the ECM and everything was fine for a while. Until we got it home of course... These head units have an anti-theft feature that means they are matched to an ECM and cannot be installed in another vehicle. I'm guessing this is what is going wrong. The dealer thought that an aftermarket suspension-adjusting compressor that was wired in might be causing a problem so they rewired that to leave the ECM out of it. A couple of weeks later the ECM has again forgotten the head unit so that wasn't the problem. So I don't have a complete answer but if anyone out there has a similar problem at least they can get some idea of what's going on.

And hence my desire NEVER to own a vehicle with such systems. EMS etc is fine, but interdependencies for IMO some silly "security" reason... Way too dangerous for my liking, plus inconvenient. Get a 2-stroke Harley. They have lost the plot if they make you CONFORM - even if it is merely to their audio system. PS - many thanks for the update. At least all the "tricky circuit causes" have been eliminated.

oldspark wrote: And hence my desire NEVER to own a vehicle with such systems. EMS etc is fine, but interdependencies for IMO some silly "security" reason... Way too dangerous for my liking, plus inconvenient. Get a 2-stroke Harley. They have lost the plot if they make you CONFORM - even if it is merely to their audio system. PS - many thanks for the update. At least all the "tricky circuit causes" have been eliminated.

I have another, final update to this. We found the root cause behind the ECM 'forgetting' the head unit. My boyfriend was poking around the fuse box doing something else when the power cut out. He discovered where the main fuse plugs in, the metal in the socket was a bit bent. When the main fuse was bumped or moved in any way the circuit would momentarily break, long enough for the ECM to lose contact with the head unit and stop playing ball. So he bent it into shape and all has been fine ever since. So after all that it was a very simple manufacturing defect causing an intermittent problem that didn't play up when the dealer's mechanic was looking at it. A big thumbs up to Perth Harley Davidson too, they were very patiently trying to figure it all out and did everything they could, never blamed us or tried to get out of it. So yes, you are right about it being a pain in the neck. The only real issue created by this loss of power is the head unit malfunction. I don't know why they would set it up like that either. I would have thought the problem should be if the head unit gets put with a different ECM, not the same one! I actually have a 2-stroke 250cc road racer from 1988 that is just as fast as that 1688cc (103ci) Harley! The security system consists of a key and a kick-start together with it's age and general undesirability. Having said that, in the US they are very rare because they were never sold there and importation of them is difficult.

MANY thanks for the update! And what a brilliant find!! That's one heck of a boyfriend. Let me know when he's free - but don't tell my GF! Intermittents are the worst problems ever. It is thru experience that I can advise tricks like ROTATE fuses to find that one in a million fractured fuse that tests and visually looks ok but fails when warm, or break & remake all connections or bulbs (and maybe scratch or Inox or WD40 spray etc) for the ~95% of electrical faults caused simply due to bad connections. But finding a bent pin in a fusebox - that's that extra bit of advise/expertise else luck and observation skill. As to Perth Harley Davidson being patient and NOT blaming you etc - c'mon - how gullible do you think I am? But seriously - pass on my sincerest respect. Tho that response and attitude should be from all - especially from expensive or classy joints - it seems to be rarer these days. Not that I blame any one or business for screaming in frustration (or friggin' words to that effect), but the customer should not be blamed... etc. Now - 2 strokes... ah my beloved 1973 RD350. Nice to see you have a modern 2-stroker. Alas I still have my two 1984 GPZ-900Rs and my 1973 GT-750 Ducati. Not that they've been running for a while (not this millennium anyhow), but I have my 1965 Isuzu ute for that. I guess 1988 is too new for the old Kwaka Machs. The Mach (2?) 350 was the only bike the RD350 couldn't touch... UNLESS like all Machs it failed to start on the first - else maybe, MAYBE second - kick. Brilliant security indeed! Anyhow, enjoy the rides. Oh - and don't be seen in a "gang" (LOL.... not!). Thanx again.