Greetings! Got a quick question today...

Anyone have some experience or test information as to the minimum per-bulb current draw which will still keep the "defective bulb" indicator turned off on a 90s 200/700? Looking to replace groupings of the existing 1156 incandescents in the tail of the car with some good quality LEDs -- which only draw about 300mA per bulb unit -- and don't want to be staring at an errant indicator lamp due to false triggering.

For reference, IPD stocks the Volvo module responsible for this indicator function here: https://www.ipdusa.com/products/22772/

Not really interested in the parallel load resistor products: I'd rather run things cool and low-current if I'm going to do something like this...

Thanks for the input!

 

The bulb failure system only cares about the brake lights, rear parking lights and the low beams. So you could replace the turn signals, reverse and rear fog lamp bulbs with no problems.

 

I appreciate the post, hoonk.

I just need info on what the minimum per-bulb current draw spec is to prevent the bulb monitoring module from illuminating the console indicator. Is this value 1 Amp, 1/2 Amp, 1/10 Amp? Has anyone tested this, or is there a "known" specification to go with???

Another way around would be folks weighing in on which 1156 LED replacement bulbs out there on the market don't allow this module to function correctly when those LED bulbs are used in the monitored sockets. This data could be informative.

FWIW, I am trying to retrofit the brake and parking lights as my primary goal...

 

1156 are not parking lights. But Yes those are brake light bulbs.

Your tag line - "No hobbies, no extra money"

What's wrong with the bulbs you have!

Sorry, it's late here. (i'm an old retired guy also)

 

Hello hoonk.

We're getting out of the old 960 as soon as possible. It's quite thoroughly aged on all points, and long daily-use is taking its toll...

A couple of reasons for my interest in replacement of the 1156 incandescents on our 740:

• These bulbs have run so hot as to have warped the internal plastic of the taillight housings.
• Good, lower-current equivalents will allow longer service life for the relevant switching assemblies (transistor, switch, or relay).

As background, this is a 32+ yearold car which has about that many K miles on it; and has been immobilized in climate-controlled storage for over 4 years. It's essentially a new old car with all that implies (supple wiring, good plastics, immaculate bodywork and paint, prime elastomers, perfect upholstery, etc.).

In the interest of good stewardship, I am looking to put this car back into service doing things as correctly as possible from a 21st century technical perspective -- as new and prime used parts are getting scarce moving forward. Unsure how long the car will presently be needed for daily service: The hope is for an additional 20 years or more. Overall, planned obsolescence is the enemy.

So that's what's wrong with the 1156s which are in place now -- along with most of the car's fluids, filtration regimes, underhood thermal management, and several other aged approaches to traditional automotive practice. In this small corner of the work, there are 9 1156 bulbs (by whatever designation) in the car's tail that I want to eventually upgrade to low-current equivalents.

What about you, hoonk? Have a story to share here about your garage? Good to see someone on the forum sharing from broad experience and official Volvo resources.

Thanks again, and have a great day --

 

Not sure if your year still uses the same bulb out warning relay as the earlier model 200's. The earlier type just senses a difference in current between the two sides to tell if one bulb is out.

 

@Johnsf:
Thanks for dropping by!

I'm betting this is the case, and that the LED products I'm getting exceed the minimum current draw spec the module requires to determine if there's a broken filament somewhere.

So, after a fair amount of digging, I ordered some decent 1156 LEDs for the work. Each unit is claimed to draw about 300mA...

We'll see what happens when the electrical system for the car is finished and energized ;o)

Cheers --

 

Update:
Electrical system just energized. New LEDs received are of very good quality. Excellent value.

Unfortunately, Volvo decided to cut corners in the design of the bulb socket panels at the rear of the sedan: The sockets are wired mostly reverse-polarity for the sake of a cheaper "wiring" arrangement. If you look carefully at the panels, you'll see what I mean. One would need to rework and rewire both panels to enable use of standard LED products.

So, as is often the case in these affairs, we've all been outsmarted by the beancounters. Nothing to see here, kids.

Now to the next item on the list --