salmon
- Thread starter kunta
- Start date
There is no hard-n-fast rule as to when you should replace those relays. However it is normally recommended to replace them every 5 years or so under normal use, but saying that I didn't replace mine until they were about 10 or 11 years old, and I use my roof as often as I can. I bought it at 5 years old, but don't know whether they were replaced prior to that, I doubt it with only 27k on the clock.
To rephrase the OP's question:
How does time affect relays compared to actual usage?
My guess is if you garage your car and there's no moisture in the trunk, time will not age your relays as much as a relay under the hood where temps vary greatly. However, as was also pointed out, they're relatively cheap.
My local BMW dealer charges $10 each over the list price, while many online retailers will charge list price or less than (plus shipping).
My best bet is to buy with other consumable parts to get up to the free-shipping threshold from places like ECS Tuning or FCP Euro.
How does time affect relays compared to actual usage?
My guess is if you garage your car and there's no moisture in the trunk, time will not age your relays as much as a relay under the hood where temps vary greatly. However, as was also pointed out, they're relatively cheap.
My local BMW dealer charges $10 each over the list price, while many online retailers will charge list price or less than (plus shipping).
My best bet is to buy with other consumable parts to get up to the free-shipping threshold from places like ECS Tuning or FCP Euro.
Under normal circumstances / conditions it'll be down to usage. This is due to the current drawn by the hydraulic pump motor and arching between the contacts inside the relay. Over time this arching can create pitting of the contacts, and under extreme cases the contacts can weld together. If this happens the controlling circuit won't be able to switch off the pump motor, no matter what you do, and then the pump will run continuously, eventually burning the pump motor out. Then you're talking big ££$$€€.
But how do we know these contacts are starting to go bad within the relay housing? Well you could take the relay cover off (carefully) and give the contacts a good inspection (having disconnected battery negative lead first, and then removed the relay). You could clean the contacts if required , but TBH if it's starting to pit that much I'd bin them and get new ones (BTW NEVER buy used ones, you never know the condition!).
But how do we know these contacts are starting to go bad within the relay housing? Well you could take the relay cover off (carefully) and give the contacts a good inspection (having disconnected battery negative lead first, and then removed the relay). You could clean the contacts if required , but TBH if it's starting to pit that much I'd bin them and get new ones (BTW NEVER buy used ones, you never know the condition!).