Those bloody headlights again ! Talk about picking the moment to give grief...........

[fatbloke-dim]

Now there's some interest in my '93 'vert , ( have to sell ,wife can't cope with gymnastics and seating position ) , the battery went flat in a week ,and it's a new one with good Amp/hour rating . I have had issues with a current drain , thought to be the headlights ,of about a quarter Amp , and a sturdy arc ensues when connecting the battery or replacing the 60 Amp main lighting fuse . Also , both headlight motors jump to attention when the connexion is made , leading me to suspect either the relay or whether there are any limit-switches in the motors themselves . Anyone have any ideas on this ? Think this be symptomatic of a dud relay ,or is another control-brain , like body control module implicated? If the relay is duff , does one relay control both the doors/motors as well as the lights? Or are there relays for motors additionally and seperately to the lights? Are these relays available new , as a web-trawl comes up with plenty o' used ones .
I usually pull the battery neg lead when the car is not used for a few days, did think about maybe just pulling the lighting fuse and seeing if that makes a difference , but time has suddenly got quite pressing now the car is on sale . Maybe it's registering it's digust at being replaced with a M()574ng !! I should add , the headlights function flawlessly and very satisfyingly smoothly .
Questions ,questions...........

 

[fatbloke-dim]

Further to the above.....

just thought I'd nip out whilst the weather was fine , and pull the headlamp control relay off , as I've read the unit can be opened , despite the warning sticker on it to the effect that it must not be opened ,only removed or replaced . A firm called Top-Down sells "refurbished" modules that have been opened and had the contacts cleaned , then re-sealed , but does'nt list one for Corvettes ,but has 'em for Fiero's and Firebirds and such ,and I believe these are the same module . So ,armed with that dire warning ringing in me ears ,I prised the back off , half expecting to find burned and maybe stuck contacts somewhere inside . No such luck !

I noted a solenoid in a clear plastic case ,the plunger of which was not in contact with any other part of the solenoid,ie., not apparently in the "energised " position . I re-fitted the relay/control mod and wired it up again , and this with the lighting fuse removed . Result- no click/motor armature activity. When the fuse was replaced , the motor woke up again . The solenoid core did not show any activity throughout all this . From this , I figure the following;-
1..the solenoid activates the current/any relay to actually light the lamps, and plays no part in the mechanical aspects of headlamp operation,and,
2.. there are some i.c. chips on the circuitboard...are these to control power shut-off to the motors ? If so , then I reckon there's nothing for it 'cept putting a new control mod in to see if it works . But prior to that, are there any other relays involved in headlight operation? Electrickery.....you gotta love it ! Or not.:ugh

 

[fatbloke-dim]

Right ,then....

more testing has revealed that the current drain is on the circuit to the E.C.M. , it turns out the headlights are'nt the source of the drain in all probability.
So ,to that end , I'll post under a different heading and see if I can cop a few tips on what may be adrift there .