Brake Pad light - Central Warning Unit

[vandenham]

The brake pad light on the central warning system comes on every time I start my car and only goes out when I push the reset button. It has been this way since a bought the car a couple of years ago.

I have installed new sensors at each wheel and have checked the continuity at the fuse panel and the circuit is closed as it should be. I also checked the continuity at the central warning unit (connections 19 and 20 on the black plug) and it is okay also.

Looks to me like the central warning unit is not working correctly. Do I need to replace it or is there a way I can take it apart and repair this one function?

Occasionally all the dash lights do not go out when I start the car and I have to start it again.

Rick

(PS: interesting note - this is an early 1978 and someone indicated the early ones were hand built. The plugs on the fuse panel were all numbered with a marker and I wonder if it was done at the factory. The two plugs on the central warning unit are black and one of them has a yellow piece of thick paper glued to it to show it is supposed to be yellow.)

[LUFTMAN]

the control unit lives under the left foot rest assy. not a good enviroment to be in water,dirt ,vibration etc.. try and spank the control units and see if dash warning lights go on and off i have seen many contol units act up like this if it does you need a control unit have replaced many of those on that model. regards tom

[Landseer]

Wow, that is an early one. (#6 has recently resurfaced and lots of current discussion on the early ones is happening)


Why not trace each of the sensor wires and wiring harness to the CE and the dead pedal using a voltmeter?

Through 84 the wiring plugs are hand lettered.

[vandenham]

Thanks guys. I've ordered a unit off ebay. Hopefully that will solve my problem.

[vandenham]

Well, my new control unit arrived and it did not solve the problem with the brake pad light.

I did a bunch of scoping with my multimeter and finally discovered that one of the brake pad sensors was grounded. The small metal spring that holds the sensor in place was touching the sensor wire. So even though there was a complete circuit through all the sensors, the control unit did not like the fact that the circuit was grounded.

I replaced the faulty sensor and everything is working like it is supposed to. This is the first time in over two years that I have not had to push the button to get the dash light to go out. I am ecstatic - hooorah!!

Rick

[Mrmerlin]

great, glad you got it figured out.......
now to clean all the fuses/relays and the 14 pin connector under the hood

[vandenham]

I've already pulled and cleaned all the fuses and relays. The relay panel still looks like it is new. The outside of the 14 pin connector looks great, but I have not pulled it apart yet. I'll do that next.

[Landseer]

A bunch of pictures of your 78 would be nice, just in general.

Lots of interest lately in the original configurations.

[vandenham]

Love to oblige.

It is an early 78 - the Central Warning Unit I just checked was dated 12/77. The car still has the original engine and tranny serial numbers. The speedo shows 71,000 miles (actually 114,000 km). It seems to be in clean original condition - I just put in new TT bearings and was surprised to see that the underside looks to have the original undercoating with good paint and very few dings (other than some $#%& from someone not lifting it properly on a hoist).

Here are a couple of pictures - if anyone wants to see any specific spots, I can take some and post them.

[riber.bentsen]

WAAAAAAAAAAAAUW!!!!!!!!!!

I'm speechless, and my keyboard needs cleaning now..

[neil30076]

Originally Posted by vandenham

The brake pad light on the central warning system comes on every time I start my car and only goes out when I push the reset button. It has been this way since a bought the car a couple of years ago.

I have installed new sensors at each wheel and have checked the continuity at the fuse panel and the circuit is closed as it should be. I also checked the continuity at the central warning unit (connections 19 and 20 on the black plug) and it is okay also.

Looks to me like the central warning unit is not working correctly. Do I need to replace it or is there a way I can take it apart and repair this one function?

Occasionally all the dash lights do not go out when I start the car and I have to start it again.

Rick

(PS: interesting note - this is an early 1978 and someone indicated the early ones were hand built. The plugs on the fuse panel were all numbered with a marker and I wonder if it was done at the factory. The two plugs on the central warning unit are black and one of them has a yellow piece of thick paper glued to it to show it is supposed to be yellow.)

FWIW - The usual cause of all the lights not going out when you start is a bad ignition switch - I've replaced a couple for this exact problem. Not an easy job and i would live with it - you have to pull the pod, etc to replace, and what is working now may not after!

[vandenham]

Thanks for the info Neil.

The dash light problem seems to have gone away - I installed the newer control unit and it seems to have solved the problem. I'll keep my old one as a spare.

I can see the ignition switch causing this problem. If I understand the wiring diagrams correctly, the problem might be between positions 2 (ignition on) and 3 (starter on). When you turn the key to position 3 to turn on the starter, the wiring diagrams show that it breaks the contact with position 2. If the contact with position 2 is not broken, the car will still start properly, but the dash lights will remain on.

[neil30076]

That's correct, and if the return spring in the switch assy is weak, it hangs up between position 2 & 3 - and the lights stay on.

[vandenham]

Can you squirt oil/WD40 into the ignition keyhole to lubricate the whole ignition assembly to make it easier for the return spring to work? Or do you have to remove the ignition assembly.

[Mrmerlin]

you can spray some WD40 into the lock cylinder not much,

it will not lube the elex portion

[JK McDonald]

Hey vandenham, What a beautiful car - the interior has also obviously been well cared for and in great condition. A 5 speed to boot - Great catch.....

Michael

[Landseer]

Well, inerxxl, try the english version yourself.

Then, after some practice, you might figure out where to post your advertisements.