Date registered: Mar 2010
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FYI very important update to intercooler pump issue on c32. I have changed my pump, but it was still not working. I drove the car without pump for about 3 to 4 years now and everything was fine, no break downs. Many years back, I took the car in to the dealer for another issue and apparently, at that time, the tech pulled my fuse and relay switch out and pushed it back into wrong slots. Thus, even with the new pump, still no go. It took 3 days to look through fuse box and diagram as well as another post and pics of other people's rear fuse box to figure out how to complete the intercooler issue on c32 models up to 2003 models. 2004 c32 apparently uses fuse in #18 instead of #5...
Open the fuse box in trunk and look for rear ebox in driver side. open up the panel and foam and on fuse #5, should be a 7.5amp fuse. check to make sure this is still good. then need to check to make sure relay next to it which is in 3rd from top position at bay C is still in the fuse box. (a correct relay switch should be black in color and have 4 prongs, in 2 + 2 perpendicular position.) Mine were empty as the MB dealer tech plugged mine back from fuse #5 into #7, and simple relay C to relay D(a white relay, not a relay switch). Relay D should be the only empty relay socket in terms of relays. If this is fully done with new pump installation, then Everything will work like magic. Remember, before doing any intercooler repair, check this step first. Even with new pump, no fuse, no relay, no go. Also, I was told by dealer that these 2 fuse/relay would normally be replaced when intercooler pump is repaired at their shop. So, maybe pick up new relay C and fuse #5. relay is about 25 bucks and fuse cheap. FYI, no one sells the relay on the internet, need to hit the dealer for this one unfortunately, so no part number is required. Oh, I called the dealer and they say that bay C is in their system as brake off switch or something like that, not intercooler relay switch. Hope this post will save a dude like me a whole lotta time and headache. Bosch SVT lightning pump works like a champ and also, no need to switch pump pipe housing either. Just get some new hose metal bolt clamps and the original hoses fit right into the new pump and no leaks. Use a large wrench and pry off old pressure clamps, and use new bolt clamps. Takes like a minute to do the pump swap.
Last edited by jjkwak; 02-03-2012 at 06:28 PM.