I have a '91 190e 2.3. I installed a new ALT, Drive belt (with proper tension), new battery, terminal posts, and checked the cable ampage and continuity.

The car runs great until a Full load on the system occurs, i.e. radio, A/C or heater, headlights, and of course braking (brake lights).

After a while of driving, the car's SRS and ABS light will come on and the car will die. The battery is totally discharged.

Prior to this, the voltage(with car running) ranges between 13.8 to 14.4; with the accessories OFF. With accessories ON, voltage ranges between 13.1 to 13.7.

No power seats, no voltage drain.

Given the conditions above; is it possible that the Overvoltage Protection relay is @ fault.

Point me in the right direction...

Thanks in Advance, Ray

Ray:

One thing that will cause a simultaneous activation of the ABS/SRS light is a weak voltage regulator or the worn brushes in it.

Not sure about the 2.3, but on the bottom side of my alt. is the VR. Two philips-head screws that are about 1.5-2.0 in. apart come out. The VR slips out and the new one goes right back in - very easy to do. New brushes on a new VR are .5 in. long. Pull your VR and see how long the brushes are.

The VR's are likely available from a local MB indy supplier - think I paid $35 for a new Bosch VR that had same part number as what came off car.

I find drive-up ramps help provide access to the bottom of the alt.

Good luck.

Thanks for your reply... I will check the ALT brushes even though the ALT is brand new.

The voltage regulator is apart of the ALT and the one on the instrument panel check out fine. The guages all operate fine also.

The ALT light (new bulb installed), never comes on while the car is being drove or when the car finally dies. However, it iluminates before the car starts @ the key turn.

Next, I will trace the wiring from the battery and battery block to the starter to ensure that no intermittent issues are looming.

Know of any fusible links!?!

Just looking for any new pointers...

Thanks again, Ray

Hello, I checked the underhood wiring completely and only found a bad ground strap coming from the ignition coil to the engine (@ the intake air plenum).

I replaced it. I removed the OVP relay and the car would not start. I cleaned the terminals (posts & plugs), reinserted it and I haven't had a problem with the battery dying or stalling after the ABS & SRS light illuminates.

My OVP part number is 38 45 !!! Wow... I ordered two replacements from www.importsportsonline.

Thanks for the great posts I have read on this site.

Ray

OVP cannot affect battery charging, all it does is to supply power to the ABS and fuel computers, and blow its fuse if the system voltage gets too high.

I think your problem was the ground strap you mentioned.

__________________
Mick J
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)

I hope it was... but I am very weary about that. You are correct about its function, but if it fails(or is removed from my car) my car will not run.

The good part is..., I drove it for about 2.5hrs last night with all of the peripherals turned on and the car did not stall or idle low as it would before.

The car as put me down many times recently with the same scenerio... radio cuts in\out, lights get dim, ABS & SRS light come on and the car dies shortly after. Even with the new ALT(& voltage reg), drive belt, and battery (700 CCA).

Once, I have just gotten of the highway(driving for about 1hr) and as soon as I applied the brakes to stop @ the light, the ABS & SRS lights illuminated and the car stalled.

Right now, I am simply watching the chain of events and hoping that the problem is resolved. I am continuing to drive the car, I don't have to, but I need to resolve this issue.

Thanks, Ray

Well, I had the same issue you went through Ray, except mine creeped in while I was on a 550mile trek back from Las Vegas to the Bay Area.

Just like you mentioned, my SRS light came on continuously, and then the ABS light. Then my radio started acting up. Finally, I noticed a gradual loss of power. First I thought it was the battery, then the alternator. After being stuck overnight in the middle of the desert, I took the car to Pep Boys for diagnostic testing. Everything was fine, they said, so off I go. Not 20 minutes into the 5 hour trip, the same thing happened again. I forced my way for another hour before I had to take a pit stop, where I coasted the car to a gas station. There we (I was being followed by my brother) jumped the car again. The I thought maybe the carbon brushes were dirty so I whacked the alternator with a fire extinguisher a few times.... and that did the trick. The car ran fine the rest of the way. Today I took out the voltage regulator and it confirmed my suspicion. It looks like the original alternator/regulator assembly, and the brushes were less than 1/4 inches long. I ordered the $15 replacement at Fastlane today.

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89 300CE
91 Supercharged Miata
99 E320 Wagon