1988 944 Turbo relays

[Guest]

My complementary driving lights under the front bumper are not working - I finally drilled off the old screws and replaced the bulbs with new H3's. The lights still aren't working. Then I decided to look in the fuse box, and I notice that the G12, G16 and G20 relays are missing.

G12 is supposedly for the complementary driving lights (ah ha!), but I popped a few different relays from altenate places around the fuse box in and the lights still didn't work - is the G12 relay unique?
G16 is for the cat gong, which I don't care about, so that can stay out.
G20 is supposedly for the ABS, but I thought my ABS was working?

So I guess my questions are - what do relays G12 and G20 control, and how do I get my lights working?

Thanks all,
Paul

 

[Guest]

An update - I tried the G12 from another 944, and sure enough the lights now work!

But what does the G20 relay do? My ABS seems to work (as in I can't lock the wheels!)

 

[Riverside]

There's a diagram on the inside of the fusebox cover that tells you what everything does []

Swapping realys around probably isn't a good idea, even if they are compatable (unlikely) disturbing 15-20 year old electronics is a sure way to get further problems (loose connections etc).

Have you checked the fuses?

 

[Guest]

That diagram is what makes me unsure - it states that G20 is for the ABS, but the ABS seems to bw working with no relay in position.

All the fuses work, used the tester to verify that.

 

[sawood12]

If you take your ABS fuse out your red attention getter light in between the speedo and rev counter should illuminat along with the ABS warning light. Are all the lights in your insturment binnacle working? i.e. when you start the car do all the lights illuminate?

 

[Guest]

OK, I just had a look at the warning lights when the ignition is turned on, and I seem to missing quite a few. Are these regulated by a fuse/relay as well? How do I sort this out?

 

[Riverside]

A useful piece of advice I read about 944s (probably applies to lots of cars) is that everything that can go wrong tends to fail-safe. What that means is that (for example) if your heater breaks in some way it'll generally fail to hot because that's the 'safe' option (better to be too hot on a hot day than too cold on a cold day).

Similarly the warning lights in the dash should come on when you switch on the ignition but have not yet started the engine, they do this as a test to prove the bulb works as much as anything else [].

I think you've tried the obvious answer (fusebox), now you need to go through a process of elimination to establish whether the bulb in the dash has blown or maybe been removed to hide the fault by a previous owner. If not & you can confirm the bulb is okay check the connections behind the instruments aren't corroded, check for a bad earth or short etc. If your option sticker says you have a certain feature the light in the dash should come on with the ignition & if the feature isn't working the bulb should fail-safe and stay on when you start the car (better to warn you there may be a problem if there isn't than to mask a problem if there is one).

It may just be the way you describe it but I'm not convinced your ABS is actually working. If you jump on the brakes do you feel a judder through the pedal, or is it just that you are not pushing the pedal firmly enough? The car does have a lot of grip & on a dry day it can take a surprising amount of effort to lock the wheels & cause the ABS to cut in.

 

[Guest]

Hmmm .... maybe if the grip is higher than I suspected, I should verify I have ABS. How do I do that without a brake test - what is the option code and where is it?

I've double checked all the fuses, and apart from one having a 20A fuse instead of 30A (since rectified), all seems fine.

And how do I confirm the bulb operation in the dashboard - can I do it without taking anything out? I really don't want to start taking off the dashboard ...

 

[Riverside]

To find out what options your car has look at the codes on the option sticker (between the tail lights in the boot, or inside the front cover of your service book and compare it to a list of option codes (type Porsche option codes into google, there are a few sources eg here) On my '89 turbo one of the option codes is 593, which means my car has Bosche ABS.

If you want to start solving problems like this you'll need to start taking it apart at some point, if you are reluctant to do so yourself your best option may be to find someone who will do it for you []

 

[sawood12]

It is worth noting that there is one light that doesn't illuminate when you turn the ignition and that is the low petrol light. This will only inluminate when you actually are running low on petrol.

My advice would be to start from the binnacle end (assuming you've satisfied yourself that all the fuses and relays are now working). It could very well be a simple case of bulbs being out. Unfortunately jobs like these usually boil down to a process of elimination so it's best to eliminate the easiest parts to access first before working through the problem in a logical manner. How many times have you searched through a big pile of paper only to find the sheet you're after is on the bottom. It's best to check the top sheets first, then the bottom sheets before leafing through the bulk of the pile.

 

[Guest]

Thanks for all the suggestions so far everybody. Looks like I'll be elbow deep in dashboard after all this weekend ....

As usual, I'll post updates on my progress. And I thought the front driving lights were the last big job ... !

 

[Guest]

Hmmm, there used to be a pictorial guide on the web for how to remove the 944 dashboard, and now I can't find it.

Little help anybody?

 

[Guest]

Never mind, I eventually found what I was looking for ... http://www.clarks-garage.com/shop-manual/elect-07.htm

 

[Riverside]

I've had the instruments out of mine, it's possible to do it without removing the steering wheel but it's much easier if you do. It's pretty straightforward & there's not much to go wrong but the surround can be a bit tricky to get back in proper alignment with the foam surround for the face vents. Be careful not to over-tighten the screws too, some of the plastic tabs are brittle & can easily crack. Take your time with it & you should be fine.

 

[Guest]

OK, had the dashboard out today without taking the steering wheel off - no need to in the end.

No bulbs in the antilock warning light, brake pad warning light, seatbelt warning light and central warning light, so replaced all these.

Now I have to get a new relay for the antilock G20, so I now have the antilock and the central warning lamp lit. I am currently using a relay from an 1991 S2, but it seems faulty as I get the warning light anyway, although I think the brake pedal needs less pressure than before.

The seatbelt light does not work - can anybody point me in a direction here?

And finally, the brake pad light is on even though the pads are not worn at all, checked all four, so something is not wired up correctly.

 

[Riverside]

I think it's probably indicating now that you have ABS & there is a fault with it, could be a (simple) faulty wheel sensor, could be something else [] Get it checked out at a specialist, you should be okay to drive the car without ABS as it shouldn't affect the brakes (they'll just lock up if you stamp on the pedal like a normal non-abs car).

Seat belt light may not be hooked up in your car & it's a low priority fix but if you want to have a look the sender is (obviously) under the drivers seat.

Brake pad waring light illuminated, as with the ABS is probably a faulty or missing wheel sensor, if your pads are fine don't worry about it too much and if you are happy to disable the circuit I believe you can just complete the circuit for each wheel with a bridging wire in place of each of the four sensors. If there is a break in the circuit the light will come on. The pad sensors have been discussed recently on this forum, try doing a search to see what comes up.

 

[Guest]

OK, so I have ABS, but looks like I also have a faulty sensor on a wheel somewhere. The car is going away next week / week after to get stainless steel brake hoses fitted, and the brake fluid replaced (it boiled on the last track day), so I'll get the ABS sensors looked at as well to see what's shot.

As an aside, when I put the dash back together, my mileage trip reset doesn't work anymore. I can see the hole in the dash that the pointy thingy from the lever on the vents should line up to, but what should be the far side of the hole that the little pointy thingy connects with to actually reset the trip? I did see a connector emanating from the dials with a small circular impression point, if you know what I mean, but I can't see how to make sure it stays in alignment with the hole, which makes me think it's the wrong thing.

 

[Riverside]

I think you're 99% there with the trip meter reset, there are two holes in the metal part of the dash (right behind the reset button on the facia), IIRC one is for a screw & the other is for a locating peg on the back of the switch to hold it in postion.

Just in case you don't know the reset button for the trip meter is just to the left of the gauge pod, it's the centre horizontal 'blade' of the fake air vent. Only push it when the car is stationary.

hth

 

[Hilux]

No bulbs in the antilock warning light, brake pad warning light, seatbelt warning light and central warning light

I would ask why they are not there [&:]

All dud but there would be ok for me but to have them all missing is odd.

Suggest you get your braking system checked for damage

 

[Guest]

I think what happened was that an abs sensor developed a fault, the previous owner didn't know what to do to solve it, so took out the ABS relay. however, that didn't solve the problem so then they took out the bulbs to stop the warning lights appearing.

I also suspect that when the brake pads were changed, the warning system was not wired correctly, so they removed that light too.

Amateurs .... !

When the fluid is getting changed, I'll have the mechanic check the system for any damage.