Tow bar wiring and smart relay
help please.
my tow car will only power the fridge when towing if I leave the headlights on,
Went back to my dealer today who condemned the battery ( new one fitted under warranty) came home plugged back onto the van still the same only 9volts at fridge unless headlights are turned on the voltage then goes up to 12v and the fridge will work, turn lights off and the fridge stops working
google the issue and the majority seem to go with a direct fused feed from battery to 13 pin socket, I just don't fancy ripping the car to bits for this, or towing with headlamps on all the time, does anyone know if the smart charging relay can be adjusted or replaced with different type of relay??? By the way it's a 2 year old Honda CRV.
Comments
-
This problem is quite common in newish vehicles and is down to the smart alternator (or not so smart), reducing output when the vehicle battery is fully charged, that is why it works when your headlamps are on. Fitting a direct feed from the battery would probably invalidate the warranty.
There is another thread regarding this,
1 -
Thanks Vulcan, I guess it's back to the dealer for a falling out session to see what they are going to do, it seems the way forward is a direct feed fused from the battery at their or Honda's expense👍
0 -
I suspect ford have updated it recently. I recently took possession of a new Smax and noticed that the fridge stays on even when the engine is off. Queried this with the towbar fitting company who think it switches off after a period of time but yet to test it and will also be with a new van anyway
0 -
As I posted in that other thread, I see this as more an issue of where the switching solenoid is being switched from:
I'm not an vehicle electrician, but I am certainly confused as to why is this an issue with the smart alternator?
The feed to the van should be from a fused connection from the battery, this should provide power regardless of what the alternator is doing, if there is charge in the battery.
The supply should not be from the alternator direct (the alternator is connected to the battery) and even if it were connected to the alternator, the alternator should not switch off due to the demand from the fridge.
The alternator should just be looking after the battery.
If the supply to the van is switching off with the alternator, then there must be a switched solenoid in the permanent 12V supply to the van, this would be normal and typically be from the ignition circuit, so the fridge cannot flatten the battery in the car when the engine is not running.
Has this solenoid been wired up to a switching supply that is somehow connected to the alternator output voltage rather than the ignition on voltage?
0 -
CJ
not sure how it has been wired, when I ordered the car I specified I wanted a Swan neck tow bar with 13 pin electrics with split charge and to run ATC and to power the fridge. It seemed ok on my previous van which had a different fridge to this van maybe new technology on this van or with it being a different make of fridge has something to do with it. But I guess I will find out on Saturday at the car dealership and they will try to blame the van and not the car.
0 -
If you are only seeing 9v at the fridge without lights on and then only 12v with the lights one, how does that second reading compare with the voltage at the battery? They should be the same. With the lights on, I and engine running I would expect to be seeing higher voltages than 12v. Have you disconnected the fridge and tested the voltage on the cable end? If not it does sound like you have a unacceptable voltage drop, which could be caused by either poor connnections or undersized wiring. Fridges do draw a fair amount of current and this would be a reason for the low voltage under load.
Before you go blaming the smart alternator off the ECU that actually controls it, I would go for the basics first.
0 -
Also check the earths. Make sure that they are clean and down to bare metal. I have experienced paint under them on new vehicles
0 -
Quick update, all sorted now, what I thought was a single direct feed from the battery to power ATC was actually sliced into twin core wire which then split in the rear, one to a relay and one to the 13 pin plug.
now have unspliced the twin core to single core to the battery and made a short fused fly lead so each part of the two core has its own feed and as if by magic, ATC works fine, fridge now works when engine is running and measured 14.2 volts at the tow bar socket and 14.1 volts at the fridge itself, now one happy bunny,result👍
0
