AUTOOL X50PLUS Car Head Display Digital OBDII Speedometer with Over-speed Alarm Function, Battery Voltage Meter for 12V OBDII Vehicles

Bought because the speedometer on a new car becomes invisible in bright light. Crazy, but the manufacturer seems to have designed it so the backlight goes off as the ambient light brightens. Since they also made the numbers off-white and the background pales grey, on a sunny summer day you have no precise idea how fast you are going. Its basically a safety hazard, and with camera enforced limits of varying speeds its impossible. This fits nicely in the corner of the windshield and shows the speed very clearly in large white digits, its not perfect but its fairly visible even in the brightest of sunny days with the sun shining directly on it, and 95% of the time its very visible. Two cautions. One, you need to check whether the digital display matches the speedometer, and if not, adjust it. This is a fairly simple process, explained in the user guide, and it works. In my own case the digital display was reading a little slower than the speedometer (which is bad, it could get you a speeding ticket), but setting the gain factor to 110% fixed it. The manual is written in rather odd English, but its understandable. Two, on modern cars the natural place to mount it may have a sort of non-stick coating preventing the sticky pad from working properly. I used blu tack, which would not stick to the top of the dashboard, but did to the drivers side pillar, which works fine. There is rather more cable than is needed for this location, so just gather it up with cable ties. Altogether this is excellent. It also has lots of other possible information displays, seems to be everything one could want, but I haven't tested them, only wanting the speedometer function.

MHD drives have possible issue where the alternator belt can snap Since there is virtually no over temperature indicator on this model, I bought this to give abnormal overheating alarm so as not to destroy the engine. Works brilliantly

Connected without problem, only real fault is cable is a little short. A little slow to update MPH and RPM displays but they may be because my car uses the slower ISO 9141-II protocol. The case could be smaller and made of better quality plastic but it works pretty well

after few months of using it has painfully slow rev counter now tried reset but still the same

It's a great little unit to tell you what's going on with your car, plus the option to read and clear the engine light codes. Fitted no problem in a Vauxhall Corsa, read and cleared codes with no issues. Only two drawbacks... The sticky pad that fixes the unit to the car is a little flimsy, I changed mine to number plate pads instead, then no issue. However......the cable to connect the unit to the OBD2 port is too short, mine was about three foot, so not long enough to do a good job of routing the cable to hide it effectively. The OBD2 socket on a Corsa is in the centre dash, so if yours if fitted elsewhere you might get away with it.

Good choice of functions but main drawback is you have manually unplug the unit from the obd port every time you start the car for it to power.Will be returning it for a refund.

Getting initial connection takes some time - as it goes through the various protocols to try to connect, it turned off my passenger airbag! It did eventually connect, but I had the warning light light on the dash to tell me the passenger airbag was off (not faulty, just turned off). I switched it back on via the Van's settings, and everything was fine. A few days later, I decided to unplug the OBD connector, and try re-connecting. I left it a few days in between just to check, and yup when I reconnected and it went through its various protocols, it again turned off the passenger airbag.

Ok,this works perfectly in my 2006 Jag Xk. Easy to set up, and the alarm for high engine temp is great.This can be set to read in M.P.H.as well.Overall would recommend this product.At this price it is a bargain.