I have 2 problems, (1). rough idle even though I changed the timing chain. the OVP has an unblown fuse in it . (2) the heater fan goes on only when it wants to if at all. The local Benz dealer wants $75.00 just to read any codes and I don't have a HHT, so any help would sure be welcome Thanks

When was your fuel filter last changed? Spark plugs??
Very possibly could be the fuel filter. That is what caused a rough idle for me.

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

What services have been done? There's about a bazillion different things that can cause rough idle. Your car can have codes retireved by an impulse counter the HHT is not necessary. The electronics on your car are not that sophisticated, meaning that if there isn't a fault light on a code check won't reveal anything.
The blower could be just a faulty switch.

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Scott Diener
89 300E
93 300E
92 Volvo 740 Wagon aka "Mutt mover"