wipers, blower, radio, power door locks , work until you turn key to start then everything works intermittent ,sometimes takes a couple minutes to come on ,then hear relay cycling on and of erratically, put van in reverse everything usually works, put in drive symptoms come back, noticed headlights flick a little and recently speedometer went from 0 to 100 the back ,and all gear selector symbols had square boxes around them ?
checked and cleaned ipm and fuses , when checking I put test light on negative and pin #86 of (I think start relay, removed) everything seems to work?? need help !!

 

Sounds like a bad battery, battery connection on a battery terminal, or a bad battery cable connection at the relay box connector. Check for corrision and clean or tighten as needed..

 

Wouldn't bad / corroded cable or battery cause van to shut off or not run right? I do get a p1684 battery code

 

Depends on where the corrosion is and how bad it is whether in a cable, on a connection or in the battery. All your symptoms indicate loss of some amount of power. Battery should read 12.3 vdc at the battery posts engine off. Should read 13.5 to 14.5 engine running. Best battery test is a load test done free at most parts stores. A boxed PRNDL indicates a failed TRS,TCM, PCI data buss failure or power problems.

12vdc at pin 86 of the start relay indicates voltage is passing from the ignition switch through the TRS and TCM and on to the relay.

TRS = Transmission Range sensor
TCM = Transmission Control Module