08 H3 Alpha high beams?

[therick04pp]

Weird one here, but looking for some input.

I noticed the other day, while driving at night, that my high beams do not work. I remember this the next day at around noon and went outside and checked it out... they worked, both passing flash (pull back) and constant on. Back to night and once again, no high beams. They do not work in either auto or manual mode. So to sum it up, my high beams only work in the daylight. Once it gets dark, no high beams. This includes the blue notification light on the dash. At night, it doesnt appear except for the quick light check on startup. During the daylight, the highs work as well as the notification light..

Multi-function switch, BCM, relay? Fuses? Light sensor? None of these explain why they work in the daylight and not at night. Not even the light sensor because even in daylight, in manual mode, they work.. I'm at a loss.

 

[alrock]

I noticed you stated that they work in daylight in manual mode. Do they work in auto mode during the day? Not that I really have an idea what's going on, but I'm curious. Have you covered up the light sensor to simulate night to see if the high beams work?

 

[therick04pp]

I noticed you stated that they work in daylight in manual mode. Do they work in auto mode during the day? Not that I really have an idea what's going on, but I'm curious. Have you covered up the light sensor to simulate night to see if the high beams work?

I did some more digging. Had them working in both auto and manual, at night and in the day. But both are intermittent so daylight is not a factor. Sometimes they work, sometimes they dont. Sometimes they will be working and then they stop randomly while im driving (manual mode). I replaced the relay already, no change. They were just working when I left the house. Tried again on the way home and they stopped working again. Got home, parked it, shut it off. Went out five minutes later and they still will not work. The dash notification lamp stops working when the high beams do, as well.

So confused. Lol

 

[f5moab]

Which relay; Headlamp or Hi/Lo Beam? Just switch relays around (if other relays in box with same part number) to see problem goes with relay (then replace) if not, relay is ok. Could also be a connector problem at the box or the BCM since the BCM controls those circuits for the relay functions.
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[therick04pp]

Which relay; Headlamp or Hi/Lo Beam? Just switch relays around (if other relays in box with same part number) to see problem goes with relay (then replace) if not, relay is ok. Could also be a connector problem at the box or the BCM since the BCM controls those circuits for the relay functions.
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I swapped both relays, no changes. I checked all the connections at the BCM with the high beams on and could not get them to flicker or anything (while they were working). I just went out and checked again while it is cold and they worked. So, it looks like the high beams stop working, after the truck has warmed up and work fine both in auto and manual if the truck is cold. That would explain why they quit after i've been driving for a bit.

Fuses are good, two new relays and the BCM connections seem tight, connected and ok.. This is sounding more and more expensive by the minute.. haha

 

[f5moab]

Some reading that might help....

 

[therick04pp]

Thanks. I have all the schematics from Schultyz website, for sure a god send. I did some more trial and error... think I found the culprit. The automatic car starter. When I start my truck with the auto starter, the little red security light stays illuminated on the dash (the truck runs and drives fine) but the high beams will not work. After 15 minutes or so after shutting it off and I start it with the key, the high beams work fine, consistently. So it seams as though the security and auto start are the issue. Im thinking of ripping the auto starter out and getting a newer one. i have had some weird issues with this starter, the remotes are both junk at this point and it is messing with things.

Will update once i nail it down further.