dbd

Due to a recent failure with my Hazard light switch, my instrument cluster filled with smoke and fused assorted wires which had melted.
I have a battery kill switch which I immediately activated preventing further excitement.

In diagnosing the failure I reviewed the wiring diagram for 928 S Model 90 Sheet 2.

The wiring flow/connections appear different from my actual configuration between the Hazard light switch and the Rear window defogger.

1. Should all the spade connections be utilized on the Hazard switch.
2. Is this schematic accurate enough to trust?

Thanks

Mrmerlin

how do you know the switch failed??
they usually work fine till they are pulled out of the pod with battery connected,
or the wrong harness gets plugged into it. the pod is aluminum and is grounded so if the switches are slid out they can sometimes touch the pod and poof Lucas smoke appears.
Cant help you with the wire digram , but its a safe bet all the damaged wires will be going back to the CE panel flip it down and examine the rear side look for melted wires in the spaghetti

dbd

Hi MMerlin

The internal components of the switch were bad. The reason I discovered this is the bulb would pop out after switch activation.

When I tried to modify the tangs to hold the bulb better, I believe I shorted the
bulb tangs/connections and the fusing of wires started as well as the bulb staying lit until I activated the battery kill switch.

I want to ensure the wiring diagram is accurate enough to prove I reconnected all the fused/replaced wires correctly. I know there are several variations due to model year as my configuration differs from the schematic.

I guess the only way to conclusively prove this is with another 90 to compare to.

Bilal928S4

Do you have the current WSM for the 90 GT?

dbd

Yes for the MY 90

gearz

I'm no expert but....

If you shorted the switch while fiddling with the connections why didn't it blow the circuit fuse? Have you checked the panel for the correct amperage fuse? None the less, AFAIK there is only one 90 MY wiring diagram and your car should be wired the same. Here is a link to a source--http://www.cannell.co.uk/928_Worksho...%20Diagram.pdf

Good luck!

dbd

Hi gearz;

Before I do any work on any electrical component I activate the battery kill switch. While attempting to
test a new bulb and with a magnifying glass I attempted to firm the connections/tangs which hold the bulb using a dental pick.
The bulb kept ejecting on activation. I then firmly positioned the bulb as low as possible. I then reconnected battery power . I must have shorted the bulb connections/tangs hence the fusing of wires.
There is no fuse in line to protect this particular circuit, so remember if you attempt the same procedure that the tangs be well separated and not touching regardless of how loose the bulb is. The ground wires are the wires which melted completely removing the covers. I then activated the kill switch.
This could of been a real nightmare if I did not have access to a battery kill switch as the damage could have been the full length of the representative wires.

dbd

Hi borland;

Ironically the bulb did not blow and remained lit, not flashing, as the ground wires fused. Somehow this wiring from the bulb connections back to the wiring harness/loom were impacted and not protected.

Would you know if all the hazard switch connections (spades) should have connections/wires attached?

Thanks

dbd

Yes spades 31 & 58. I need another 90 to look at where someone has
the POD off to compare wiring configurations. I don't want to experiment with
config changes, hence my reluctance to continue.

I wish someone could state definitevely whether the wiring diagram or a portion
thereof is accurate enough to troubleshoot with.

dbd

Making some progress, I am stuck on the rear window defogger switch spade 86b. The wiring diagram shows no wired connection to 86b however it does appear to be switched from 86 and 86a.
Any ideas on this?

Thanks

dbd

Hi borland;

Thanks, I am quite familiar with the operation of all switches as I have had this car since 1990.

The hazard and defogger switched are linked denoted by the diagram.

86b now has no connection.

The hazard switch works when activated, however now I am blowing fuse No.9.
which controls the ashtray and instrument lights.

I have now followed the diagram exactly as depicted.
Obviously this diagram differs for MY 90

jon928se

DBD

I found a couple of places where the WSM wiring diag did not appear to match the wiring on my early 90GT. In my case it turned out that the 89 wiring diagram corresponded to the area that did not match the 90 diag.

Suggest you take a look at the 89 and 91 diags to see if they match.

dbd

Hi jon928se;

Thanks for the confirmation, I will try the 89 & 91.