DRL - did all Suburbans have it?

[618 Syndicate]

Ehh? Totally lost! Is there an answer to my what are....

BAG PARTS PKG EXPORT and,
EXP EXPORT - I.E.S. EXPORT - I.E.S. ..... there?

Yeah sorry, I should have been clear.

 

[df2x4]

Unless the DRL module contains the resistor or, uses PWM?

I believe the latter is the case, not positive about that though.

 

[GMCTruck]

It is the components in a system that 'set' the current - and the voltage in any particular place as a consequence so it will be a lower voltage arriving at the bulbs that reduce their intensity.

What I'm not quite getting my head around is that to dim the bulb there would have to be a resistor - which will generate heat. I thought on first looking that the big finned thing was it but it is the diode and is on the switching side of things anyway. Unless the DRL module contains the resistor or, uses PWM?

In the schematic that i posted for the 1995 DRL, it looks to me that the module controls the DRL relay. When it is activated, the power for the DRL comes from fuse 15 and if you follow the schematic, the hi beam lights are run in series. Regular lights are run in parallel. I think that accounts for at least some of the reduced brightness for the DRL.

 

[Pinger]

In the schematic that i posted for the 1995 DRL, it looks to me that the module controls the DRL relay. When it is activated, the power for the DRL comes from fuse 15 and if you follow the schematic, the hi beam lights are run in series. Regular lights are run in parallel. I think that accounts for at least some of the reduced brightness for the DRL.

I thought you'd cracked it with that but looking at the Haynes wiring diagram what I see for normal low beam operation is, from the dimmer switch, low beam is fed to through the DRL in its resting position and then to the headlamp.
When the DRL relay is activated by the DRL control module, that connection is lost and the feed though the relay is now via fuse 15 and the diode. I think it is the diode that reduces the intensity of the dipped beams as DRLs - and would account for its generous finning. Also, there's no other reason for the diode and, as the control module controls the relay coil (not the outputted voltage) PWM would have the relay chattering.

What I can't explain though is how my low beams can work with the DRL relay absent as its 'resting' position is the conduit for normal low beam operation (and has to be disrupted for DRLs at reduced intensity) - unless this was catered for during my T62 DELETE DRL. Maybe someone can try removing their DRL relay and see if their low beams are still present or disappear.

The above from Haynes - I haven't checked that the schematic is the same or not though probably it is.
Anyone want to comment on my take on this?

EDIT PS.
Looking at the 'schematic, it doesn't have the diode in line between fuse 15 and the DRL relay as shown in Haynes and in the second repair video df2x4 posted.

 

[GregB]

all because one province in Canada requires them? LMAO it's also one of the smallest and has a very small population.

I'm sure there are places in the US that require DRL but I am unfamiliar with them.

after doing the 4 high and low mods I pulled the fuses from both trucks.

I however want to make my own DRL circuit but put it on a switch and use some different lights, not the headlights.

Its not because of only one Province. DRL’s were mandated by the Transport Canada (The Federal Government ) and every new vehicle sold in Canada since 1990 has had them. Personally I think they are a great safety feature.

 

[thegawd]

although your right, there really was only 1 province that did indeed require DRLS in Canada but now there are 2. Nova Scotia and New Brunswick require daytime running lights.

as of 2020 all vehicles destined for the Canadian market require daytime running lights AND daytime running taillights.

these still are not requirements in Ontario or most of Canada.

If the police in your province do not have DRLS, then no DRLS are required.

 

[GMCTruck]

I thought you'd cracked it with that but looking at the Haynes wiring diagram what I see for normal low beam operation is, from the dimmer switch, low beam is fed to through the DRL in its resting position and then to the headlamp.
When the DRL relay is activated by the DRL control module, that connection is lost and the feed though the relay is now via fuse 15 and the diode. I think it is the diode that reduces the intensity of the dipped beams as DRLs - and would account for its generous finning. Also, there's no other reason for the diode and, as the control module controls the relay coil (not the outputted voltage) PWM would have the relay chattering.

What I can't explain though is how my low beams can work with the DRL relay absent as its 'resting' position is the conduit for normal low beam operation (and has to be disrupted for DRLs at reduced intensity) - unless this was catered for during my T62 DELETE DRL. Maybe someone can try removing their DRL relay and see if their low beams are still present or disappear.

The above from Haynes - I haven't checked that the schematic is the same or not though probably it is.
Anyone want to comment on my take on this?

EDIT PS.
Looking at the 'schematic, it doesn't have the diode in line between fuse 15 and the DRL relay as shown in Haynes and in the second repair video df2x4 posted.

The 1995 trucks may be unique in that they used the hi beams for the DRL. I don't see a diode in the schematic. I will have to check my truck and see if I have the diode with the heatsink. You are probably correct tho, the diode is probably used for its forward voltage drop and that accounts for the large heatsink. My Haynes manual is the earlier one, it only has 1988 - 95 and doesn't seem to have the headlight schematic. In fact, it has very little about the 95 in general.
The schematic i posted is from the GM service manual but definitely shows the hi beams wired in series for DRL.
Its a mystery.

 

[GMCTruck]

Its not because of only one Province. DRL’s were mandated by the Transport Canada (The Federal Government ) and every new vehicle sold in Canada since 1990 has had them. Personally I think they are a great safety feature.

As with any new feature, I originally didn't like the DRL. Didn't like having to wear a seat belt either, ha ha. But I agree, the DRL feature helps see vehicles earlier than without. I was worried about having to replace bulbs all the time but in the 24 years I ran the factory hi beam DRL, I think that I only replaced the bulbs ONCE.
I see a lot of vehicles with burned out or deleted DRL so it doesn't seem to be a big deal, at least in Alberta and Saskatchewan.

 

[Schurkey]

DRLs were a GM thing. They played it up like it was the greatest safety innovation since the seat belt. Some other manufacturers followed on, but it eventually faded out.

I wish it had "faded out". More manufacturers than ever are foisting that crap on us.

If DRLs are what I think they are - they come on (front only? - which lights? - park or beams? dipped or main?) with the ignition and go off when lights are switched on via the dash switch (park or headlamps or both?)

Depends on the vehicle. Some use low-beam headlights, some (real morons) use the high-beams. Others use non-headlight lamps on the front.

are they deleted by merely pulling a fuse or connector or is a resistor or the likes required to keep the rest of the electrics happy?

Depends on the vehicle. In general, the newer the vehicle, the more-difficult it is to defeat the stupid things.

DRL illuminate the low beam headlights at half power or something like that.

Again, depends on the vehicle. Some don't use the headlights at all. But those that do, use lower-power so the headlights aren't "full" brightness.

Still too damned bright.

What I'm not quite getting my head around is that to dim the bulb there would have to be a resistor - which will generate heat. I thought on first looking that the big finned thing was it but it is the diode and is on the switching side of things anyway. Unless the DRL module contains the resistor or, uses PWM?

PWM, far as I know.

Personally I think they are a great safety feature.

There's not one "scientific study" that's been peer-reviewed for errors and bias, that shows they do any good.

Every "study" that's been done on them has been from high-lattitude countries; primarily Baltic. Countries that get less natural daytime sunshine than the USA (except Alaska) and which tend to have socialist governments so the people are used to excess government intrusion.

Turning lights on in the daytime is silly. Greyhound buses did this in the '60s, and they QUIT using headlights in daytime because after years of collecting data, they realized that it didn't make any difference. Even God turns out the lights in daytime--fireflys and other bio-luminous creatures don't glow when the sun's shining.

DRLs are nanny-state nagging, and they became an inexpensive "selling point" and "advertising point" for GM, which has spread like a virus throughout the industry. I wrote to GM asking for copies of the scientific studies proving their effectiveness. They sent me PRESS RELEASES because there is no evidence. It's all propaganda and lies.

 

[LVJJJ]

No DRL's on 94 Burb, but I installed LED driving lites at the top of the grille, mainly for when we travel in the Southwest desert on two lane roads. When the sun is brite its hard to see cars coming in the other lane when you try to pass. So figured that approching cars would have a hard time seeing me if I'm passing so installed the LED's so they could see me coming. Use them here in rainy Washington too. The are wired direct to the battery.