I installed a $20, rectangular, red LED, digital VM and connected it to 14 AWG wire powering a 12 v. cig lighter outlet using Posi-Taps, connected to my fuse block. After about 20 engine run hours I have the following: 10% of the ERT there is no display in the VM; 40% of the ERT the VM slowly fluctuates between 13.9 and 14.2 and it usually does this at idle; the rest of the time it wildly fluctuates between 10 and 20 v, going up and down the scale and it especially does this on acceleration from a stop light. It has power, and I "feel" if I got another one nothing would change. Any ideas? Thanks.