Hi Bulletpoof,

>The car that won't accept LED replacement bulbs is my XC70.

Is your standard lamp a 9005 or H-11?
Have you tried and failed?

My local friend just put a set of Rimthhin (Amazon) LEDs and he likes them.
See here for about $27, less money than high end halogens:

Select what lamp fits your car. Verify fitment with Amazon, send them back if it
doesn't fit.

https://www.amazon.com/rimthin-H11-Bulbs-Lights-Waterproof/dp/B0DCBFL289

>Yes, If it were my old 240 this would be no problem, provided I had switched to E codes w/ replaceable bulbs.

Yes, it would not e a problem either way since you order either a 9003 OR a 9004. The only difference being the connector.

>I have not found the halogens to have a short life span. I'm still on the same >bulbs that were in my car when I bought it seven years ago.

Some people hit the Billion dollar lottery.
Go here and read from the car wizards:
https://www.autozone.com/diy/headlight/what-are-the-different-types-of-headlight-bulbs

Halogen bulbs typically last around 500- 1,000 hours,
HID bulbs around 2,000 to 3,000 hours
LED bulbs can last 25,000 hours or more. (Forget fanless LED headlights)
Replacement frequency depends on usage and individual bulb lifespan.

>So how hot does a 70 watt LED bulb get?

The LED junctions get hot, that's what the heat sink and fans are about.
Overall LED's make more light than heat and halogens make more heat than light.
That's why LED's are more efficient. What you want is the most light with the
lowest power input.

Read this article about controlling LED junction temperatures
https://www.auxito.com/blogs/news/auto-led-headlight-bulb-heat-dissipation#mark-2

The wiring in my 850 headlight housing was baked from the original halogen heaters and the housings with halogens are essentially toaster ovens.
This is a benefit in snow and ice storms only.
It's also a PIA when the insulation starts falling off your headlight wiring.
Volvo doesn't use Teflon insulated wire to withstand that heat.

Read "Kittys Gray Volvo" recent posts about LEDs and "CRAPPY HALOGENS", finally a believer in LED headlights after a year of me bending his ear.

Have a happy weekend, Bill