And why did you throw money away like that? There is no "mechanic" that understands even ohm's law in the entire USA. There WAS, years ago, but no one wants to learn anymore.
WHy not just take it to a dealer and pay them $1000 to not fix it - don't waste money unless you waste a TON of money.

Am I forgiven for laughing at that question? Almost ALL of us have dealt with this. Not a WEEK goes by that someone on one of the Fakebook pages goes thru this.
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Back to topic:
This is, again, about the OLDEST complaint with our cars there is. DO NOT pay anyone to "diagnose" it. Virtually NO ONE understands the communications between the Battery, Alternator, Brake controller, BCM, RCM, ECU and CLP/SSM - and all those components have a hand in the operation of the wing.

Here is what I do when someone brings me a car with this issue:

1) Do James' ground mod, cost is $20 or less. CLICK HERE and DO JAMES' MOD, not the mod I talk about in that thread.
1A) Inspect both battery posts/cable clamps. Remove clamps from posts and verify things are clean, use a wire brush on the posts and clamps.

2) Is the battery over four years old? If so replace it.
(If you say, "I had it tested and they say it's good", slap yourself REALLY HARD until you pass out. There is no 'test' for this, as the issue is lack of capacitive reactance in the old battery, not low capacity. Ask the guy to explain "capacitive reactance", if he can't, and we both know he cant, ask yourself what you expect him to do.)
"But Mark, I don't want to waste $150 on a battery that was not the issue". Fine, go pay some shop to "Test things" and get nowhere. $150 for a battery that is that old is not a waste of money anyway.

4) If you have a BAS/ESP light on the dash at times, THAT IS YOUR PROBLEM. Ignore the wing and fix the real issue and your wing will work fine.
4A) The brake controller relay on the RCM can cause odd issues, but if that is the issue, you usually will have a BAS/ESP light at least part time.

5) Put your spare RCM in and see if that solves the issue. If it does, send your 'bad' RCM to DJ for rebuilding, cost is $60 and you will then have a spare again.
5A) If you have no spare RCM and have been a member here more than six months, slap yourself really hard as in step 2) above. I DO NOT drive the car without a spare crank sensor and a spare RCM in the trunk. ANYTIME the RCM acts up, I put the spare in and send the bad one to DJ. (Actually, have only had an RCM failure twice in twelve years, and Iv'e owned three Roadsters in that time.)


The "wing goes up" issue is as common as low tire pressure or the car getting dirty. There are SO many causes but usually it's unstable voltage/spikes/surges in the 12 volt supply that (apparently) cause the brake controller to misinterpret wheel speed data and in turn, tell the BCM to raise the wing. This is not always the battery but it is very often the battery. As the cars age, the block to chassis to battery ground path degrades, hence why James came up with his mod in 1) above.