as yous know already do plan to tow a van with the ba its just a matter of when, just a few things to ask
1. just to drive around town to get used to it will there be a rush to finish wiring up the electric brake controller and hope that you can find a van that still has override brakes to use or would you be better off finishing it so you have the option to tow vans with both electric or override brakes and are a bit easier on options meaning be prepared and more flexible with whats avaliable.
most newer vans have electric brakes and it seems only ones from 70s or early to mid 80s have old override brakes and most from late 80s on seem to all have electric brakes
the brake controller is in and the wires are there ready just hasent been finished wiring yet
2. would the ba be able to tow a aunts crussader van just quietly around wallaroo north beach area on a 1600kg tow bar if the vans not fully loaded and the brake controllers been wired, the vans about 18-20 feet long and tare is about 1400-1500kg.
3. would the radiator in it be upto towing or should you replace it with a bigger one even the water pump especially of theyre still original or you dont know when they were last changed if neither is currently leaking, do plan to get hoses done soon as possible or next service, have got a transmission cooler with a bypass setup though, just need to finish wiring up the electric brake controller and go through connections and test for power at blue wire in trailer harness
The only two things which can realistically cause issues like that, is either AC Ripple interference from bad diodes in the alternator rectifier,
(both the Speedometer (transducer) and Tacho (distributor PIP hall sensor) are AC reluctance sensors - ie, they generate a small AC voltage)
or a high resistance connection -
a positive or earth connection, common to both the speedometer, tachometer/distributor/coil.
ie, you're losing supply for minuscule amounts of time.
Main power relays near the brake booster can fail as they warm up.
Don't play swaptronics, look for commonalities between the affected components -
Is there any pattern to the problem occurrences?
ie, after x amount of run-time, or only in hot/cold weather, etc.