Hi, I’m after some advice as I’m stuck.i have a 93 sapphire Cosworth.
Both the instrument warning cluster and both the washer and fuel level lights no longer work. I took the units out, and swapped them with the ones from my XR4x4 (same) and the units are fine. The fuse is fine. The plug connections are all good.
its odd the whole lot doesn’t work, is there something else I should be looking at?
is there perhaps an additional module or ecu that also needs checking or some kind of common earth? If so where to locate…. Help most appreciated!! Cheers

 

What do you mean exactly with the 'units' are fine? Do you mean the panels with the lights on, or the electrical modules behind the dash? There are 2 modules, one does the warning lights for the head and tail lights and the other module controls the door ajar lights, low fuel and washer level and the outside temperature warning lights. Both these modules are powered from fuse 22 and have the earth on the steering column bracket.

I would first check fuse 22.

Then start with checking both modules . If these are OK I would check if 12V comes to the modules (pin 2 on the lamp module and pin 17 on the door ajar module). Also check if the earth on the modules is OK (pin 6 on the lamp module and pin 16 on the door ajar module).

 

Hey Marc thanks. Fuse 22 is ok, swapped from my 4x4. The dash pod warning lights are all ok, which indicates the fuse connection is also good.

Yeah the panels…it’s the warning pod with the car shap next to the clock that’s dead, along with the 2 level indicator lights that sit above the clock.
Where exactly on the steering column is the eart for this lot… is it difficult to access?

when you say modules do you mean they are like mini-ECUs that sit somewhere? I cannot see anything under the glovebox apart from the main ECU and some other ecu sitting on the top with what looks like a massive red plug … I would like to locate these you mentioned..cheers

 

The location of the earth on the steering column bracket is behind the instrument cluster that houses the speedometer. But I would not expect a problem with the earth just out of nowhere.

The modules I mean are indeed a sort 'mini ECUs'. On a 90-93 Sierra I believe the door ajar-module is clamped to the backside of the panel where the small glove compartment is on the driver's side and is easy to reach. The lamp check module is mounted high on the bulkhead behind the dashboard on the passenger side and is quite difficult to reach. But I could be that the modules are in opposite locations.

I believe the door ajar module supplies power to everything. So if that one is broken I think the whole system no longer works.

 

Hi mate that’s really useful! Thanks so much.. I’ll have a look tonight! Cheers!

 

Hi Marc , sorry for delay. Looked at the ecu on the drivers side under the trim, connections fine, I then found the other one exactly where you said on the bulkhead behind the top ecu cover. I managed to find a replacement from a scrap Sierra and swapped it out. Part number 87BB10K910AB 012933 84596B
As soon as I did, everything lit up like a Christmas tree!
thanks for the info, really appreciated.
off to the RS annual meet at Mallory park the w/e so nice to have (most) things working!
cheers! 🍺