need help, advanced advice please.

[bernard54321]

okay just bought a 1991 525i 5speed, here is whats going on so far:

random flashing check engine light, w/ slight misfire
code1231
surging / pulsing headlights, and interior lights

okay so based on whats known the code 1231, i wanted to check the alternator and voltage at pin 26 of the dme control unit.

now my question is, where is the dme relay, the dme control unit, and how difficult is the r&r process for the alternator? (any special tools needed?)

thank you in advance guys...

[BonnschE30]

Not sure about the relay part of your question, but check the passengers firewall for access to the dme. Pop the cover off and you should recognize things pretty quickly. Alternator is an easy job, all you will need aside from your basic socket/ratchet combos is a 8mm hex socket to relieve the tension pulleys for the ac an serpentine belts. Pop off the circular black covers on these and you'll figure the rest out. After that its 2 bolts and 2 wires to the back and that's it. Had mine rebuilt for $70 which is better that $215 for a new (remand) Bosch unit...

[AndrewBird]

Relay is right next to the dme in the box under the hood on the passenger side. It will be white I believe, orange is fuel pump.

[Onizukachan]

Or just check it on the OBC...

Even easier since you can check it whilst driving.