DRL - did all Suburbans have it?

[Pinger]

Quick way to tell is pull your dash fuse panel on the driver side and look for the drl fuse

Fuse is missing - and I've never seen that green light.

They stay on constant until you physically turn on the headlights. Makes them brighter

So mine are deleted by the fuse being pulled - and possibly more to disable the green dash light?
Could this deletion (or partial deletion) cause my headlamp switch to heat up? It only heats up when switched to headlamps so not the dimmer resistor which was previously suspected.
I've also done the 4-Hi mod (with 3 relays) and the heating of the switch is since that was done - but I can't be absolutely sure that it didn't heat up before the mod - I might just have not noticed it.

 

[Pinger]

Only thing is, the DRL system has enough current to switch on the relay, so I had to pull the fuse for the DRLs to avoid the low beams being on all of the time.

So dimmer DRLs not possible with relays - only the self switching to dipped beams?

 

[SUBURBAN5]

I dont think it will cause it to heat up. Could be the factory did not equipt your burb with it. Really doesnt hurt anything. Now if you changed your wires or added relays I suspect wrong size wire could be used if its heating up hot. Indicating high resistance

 

[Pinger]

I dont think it will cause it to heat up. Could be the factory did not equipt your burb with it. Really doesnt hurt anything.

Now if you changed your wires or added relays I suspect wrong size wire could be used if its heating up hot. Indicating high resistance

Measuring resistances, between ground and the yellow wire that handles headlamps I'm seeing 2.1 and 2.2 Ohms - depending whether the stalk is on dipped or mains. Relay's coil resistance is supposed to be 100 millieOhms (0.1 Ohms) but I don't know if there is anything else on that circuit. It also includes the stalk switch (which for some reason is missing the 'flash' function).

Across the switch contacts I'm seeing 0.9 Ohms - but 70 - 130 Ohms over the contacts for the park lights switch. That's assuming I'm measuring correctly.

I'll do more tomorrow to check the relays and understand better the DRL module and relay. Pretty sure my 4-Hi wiring is robust enough. See pic below. Green wire is signal to the relays (tapped from the bulb connections) and stouter wire that the headlamps original feeds.

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[thegawd]

you did check that the heating air duct is not blowing on the switch right? are you using a infrared thermometer to measure it? I have one of those and it's fun to play with.

 

[Pinger]

you did check that the heating air duct is not blowing on the switch right?

Yep, not getting caught by that!

are you using a infrared thermometer to measure it? I have one of those and it's fun to play with.

No infrared, just noticed it warm to the touch when switching the lights off - warmer than it should be.

 

[df2x4]

So mine are deleted by the fuse being pulled - and possibly more to disable the green dash light?

From what I've read if you disconnect the DRL diode (blocky module with finned heatsink under the driver's side dash) you will disable DRLs and eliminate the green indicator light in the cluster. I'd guess that's what's going on, or the indicator light in your cluster may just be burned out.

These videos may be helpful.

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[Pinger]

Thanks df2x4 - videos were very helpful in figuring that someone has done a pretty comprehensive delete job on my DRLs. Missing are fuses 9 and 15, the relay, the diode - and I couldn't find the DRL module either but suspect it is still there somewhere.

Dug into the box where all my relays for the 4Hi mod are, disconnected the signal lead to the dipped beam relay and the current on the switch block (between red and yellow wires) fell to 0.02A. So nothing from the DRL system hanging on the wires drawing current (the reason for this thread).
Reconnected the relay and the currents are 0.18A on dipped, 0.42A on mains. Which are pretty low and not what I'd expect to heat up a switch. The same readings earlier were 1.8A and 2.0A and there's no explanation for that. Similarly, the resistance values are totally different today. All I did was disconnect/reconnect that one relay signal wire - which might suggest that there was a fault within it that disturbing it fixed. But that doesn't account for yesterdays weird readings on main beam when that dipped beam relay isn't in the circuit.
Given that the current across the switch is now acceptably low, I'll run with it for now and see what transpires - and because I can't think of anything else to check even though the currents and resistances are so out of whack as to suggest voltages of 5.4 and 3.4V!

Thanks for all the help everyone - appreciated.

 

[618 Syndicate]

@Pinger what year is your burb?
Removing the box under the dash does not disable the green light on the dash.

 

[Pinger]

1999.
I've never seen a green light on the dash. The only thing that can remain of the DRL system is the control module - and I suspect it is still there as it is a junction for the yellow wire that goes to the dip/main switch and unless the wires are tied at the connector removing it would require the wires be spliced - if that's the 'box' you are referring to. Apparently, it has a circuit board inside that can be removed.
But I can't see any sign of the module or its redundant connector despite the (first) video df2x4 posted giving me an idea of what to look for and where.
I'm happy it isn't causing any problem if it is still present - so it gets a free ride - for now at least.