Experiencing the dreaded SRS light illuminating on your Benz 500sl dashboard can be more than just an annoyance; it can trigger limp home mode, significantly impacting your driving experience. For owners of the 1991 benz 500sl and similar models, this issue is becoming increasingly common. Like many others in online forums dedicated to Mercedes-Benz vehicles, I’ve recently dealt with a frustratingly frequent SRS light and subsequent limp mode activation in my own 1991 benz 500sl. Initially sporadic, the problem escalated to a daily occurrence, sometimes happening multiple times within a single day.
The online consensus points towards the Electronic Throttle Actuators as the primary culprit behind these symptoms. While a full replacement of these actuators is often suggested, the high cost associated with this repair is a significant deterrent. My long-term plan involves a thorough inspection of these actuators, specifically focusing on the wiring, as detailed in resources like v12uberalles.com. This detailed guide suggests that rewiring the actuators can be a viable solution, potentially saving significant expense. However, this is a time-consuming task that would render my benz 500sl unusable for an extended period. While considering the rewiring process, I contemplated simplifying it by using heat shrink tubing over the existing wires, rather than completely replacing them, which would minimize disruption and only require disconnecting one end for soldering. The core issue appears to stem from the degradation of the wire insulation over time.
Seeking a more immediate, albeit temporary, solution to get my benz 500sl back on the road, I opted to disable the Automatic Slip Regulation (ASR) system. Drawing inspiration from discussions about installing a RENNTech ASR defeat switch, I implemented a similar approach by physically disconnecting the ASR system. This involved identifying and cutting three specific wires within the wiring loom leading to the ASR (and ABS) computer. After carefully pulling back the insulation to access the wires, I cut the blue/white, brown/blue, and brown/yellow wires. These were the same wires that are interrupted when installing the RENNTech defeat switch, which essentially allows for toggling the ASR system on and off.
Since performing this modification, my benz 500sl has been driving exceptionally well, and the persistent SRS dash light is no longer an issue, as I have removed the bulb. While the snow traction control switch LED remains illuminated, this is a minor inconvenience I am willing to accept.
In my typical driving conditions, traction control activation was infrequent. Living in Australia, I rarely encounter snow or ice, and my driving experience predates the widespread adoption of traction control systems in high-performance vehicles. Furthermore, the installation of a first gear start device in my benz 500sl previously made it even easier to induce wheel spin.
I wanted to share this experience as a potentially helpful quick fix for other benz 500sl owners encountering similar SRS/ASR problems. Beyond this temporary solution, I am also curious to understand if disabling the ASR system in a benz 500sl results in any performance gains, such as increased power. Additionally, I would appreciate insights from the community regarding any other advantages that might be gained by installing a dedicated ASR defeat switch in a benz 500sl.
