I posted this in my restoration thread but thought I'd start a separate thread to increase visibility too!
Recently my EAS has started to mess around. It would lower the front when driving, when arriving at home it would have the front left sitting much lower then the rest of the car and it was generally mucking around. I noticed that one of the rear height sensors was broken so I replaced them with a pair from Autodoc. I'd never heard of them before, they were made by a company called Meat and Doria and came with a 2 year warranty. After a bit of Googling, it turns out they're a fairly well respected brand.
I fitted the rears and swapped the fronts from side to side so they were on the other side of the track and it still wasn't right. I changed both height sensors and stupidly I took the cheaper option and bought 2 from eBay. They were just shy of £50 and again came with a 2 year warranty. After fitting them I've spent hours trying to get the car to take a calibration with Testbook. Sometimes it would but the heights would be all wrong after it, other times it just wouldn't calibrate at all.
Tonight, I removed both sensors from the car, connected a meter to them and worked them through the range of movement whilst taking resistance readings. The results are awful, not only are some of the readings miles from where they should be, the jitter on the meter is mad!
Here's the right hand sensor:
You can see with the arm at the top it was 2.0k Ω, then it went to 1.7k Ω, then 2.35k Ω, 2.14k Ω, 2.35k Ω, 2.7k Ω, and 7k Ω. The 7k Ω reading looked horribly wrong so I moved the arm through a cycle and came back to it and it was 2.8k Ω so the readings are all over the place!
Right hand sensor jitter video... (There's almost 1k Ω jitter with the sensor arm in the same position!)
Here's the left hand sensor:
At the top, it started at 1.28k Ω, then 1.8k Ω, 1.5k Ω, 1.76k Ω, 1.98k Ω, 2.37k Ω, 2.52k Ω and 3.7k Ω. I went back to the 2nd position I measured at 1.8k Ω and it then read 1.6k Ω. Again, the readings are all over the place and are very different from the first sensor.
Left hand sensor jitter video... (There's only about 200ohms on this one).
The next video I took was with the sensor sat on my desk, the meter connected to it and me not even touching it at all. The minimum reading with the arm stationary was 4.441kΩ to 5.796kΩ.
Marty measured one of the older style Dunlop sensors this morning, he got a range from 200Ω up to 1.8kΩ with very little jitter!
So, I think the moral of the story is, don't be cheap and don't buy anything other than genuine Dunlop height sensors!