[V8] European headlights versus Autocheck system

[Buchholz, Steven]

... this is from an old post, but I thought I would correct a bit of
misinformation ... in any event the final conclusions are correct ... 

The autocheck system senses current difference between the path to the
left and right low beam filaments.  It doesn't matter if we're talking
about 55w or 100w bulbs, as long as they are the same the circuit will
be OK.  This is why if you use two relays you will find the autocheck is
happy.  The thing is ... no matter what ... all the auto check will be
reporting is whether or not the coils on the relays are conducting
electricity.  Since relays rarely fail this is not terrifically useful
(IMO).  

You can retain the function of the autocheck system if you would like
... all you need to do is to jumper the feed lines in the fuse box (I
think Ingo posted the procedure for this) ... then you move the auto
check relay to the box that has the headlight relays and wire the lamp
filaments as they were in the circuit without the relays ... there is a
single wire that will need to get fed back to the empty slot in the
relay box to connect up the fault signal ... 

Steve B
San Jose, CA (USA)
> 
> All the autocheck does is check for current flow through the 
> low beams when they are on. If current flow is too low, as in 
> an open in the circuit, the autocheck tells you. By using two 
> relays, you may increase the current flow enough to fool the 
> autocheck. At any rate, only the low beams are monitored, so 
> it is the side that would need the two relays. I can't 
> imagine two relays taking enough current to fool it, but 
> maybe it only measures for a small current flow versus none. 
> I never thought of this when I did mine, so I just jumpered 
> the autocheck. Even with two relays installed in the low 
> beams, it won't tell you when the headlights are burned out. 
> It would only tell you if one of the relays is bad.