Electrical boffins required!

[chrisbladen]

Hi, im just getting to the end of a complete rebuild and just re fitted all the wiring and harnesses. Everything seems to be working ok other than my wiper motor and my indicators seem to be very tempremental... everything was working prior to stripdown.

If anyone can advise what i can do to test what could be the issue i would really appreciate it.

Wiper- not doing anything at all when i turn the switch, iv checked with a multimeter and i am getting power to the switch and also power to the motor connection(i just tested across all prongs and only 1 is showing 12V). i have stripped the motor down and painted it and checked its all free inside etc. On the switch only 3 lugs have connectors on them, the uppermost 1 doesnt have anything conencted to it, i believe i have reconnected it as it was because i labelled everything up but theres a chance i could have missed 1. Also the complete unit turns as i turn the switch so i have to hold it at the back of the dash to turn it, should it have a plate or something to stop this happening? 

Indicators- wasnt working at all and then when i connected the hazard up they work intermittently but on the front offside indicator cluster the side light is flashing rather than the indicator. 

 

Any advice is greatly appreciated, thanks.

[chrisbladen]

Just as a side note iv found the cable that i think was missing at the switch, the brown/green cable and connected that up. Iv tested at the connector and between the black and green cable is 12v, but there is no voltage at any other connector no matter what setting the switch is on.

[dougbgt6]

Chris,

There should be 4 wires on the wiper motor, you have a Spitfire I think? This diagram may help.

Intermittent operation, I would suspect a dodgy earth. 

Doug

[chrisbladen]

Hi doug, not sure if you posted at the same time as my second post, but yeh i found that diagram that tou posted on the internet and i found what i believe to be the missing cable as now i have the same colour cables at the switch that i have at the motor.

Testing with a multi meter i have 12v between the black cable at the motor and the green cable, but then no voltage at any of the other connectors when i am operating the switch

[GrahamB]

When the dashboard switch is off. you should have 12 V between the black (earth) and green.

When switched to slow there should also be 12 V on the Red/Light Green

When switched to fast there should be 12 V on the Blue/Light Green

The Brown/Light Green is the return to the switch from the parking mechanism.

This assumes that you have the later twin speed wipers as fitted to the 1500 Spitfire.

The problem with the wiring diagram posted previously is that it is for the USA export models and there are several differences compared with UK models.  However, the coloured diagram is easier to understand than the black and white version in the workshop manual, just do not start looking for your bulb check relay and several other components! The following diagram may help:

[chrisbladen]

42 minutes ago, GrahamB said:

When the dashboard switch is off. you should have 12 V between the black (earth) and green.

When switched to slow there should also be 12 V on the Red/Light Green

When switched to fast there should be 12 V on the Blue/Light Green

The Brown/Light Green is the return to the switch from the parking mechanism.

This assumes that you have the later twin speed wipers as fitted to the 1500 Spitfire.

The problem with the wiring diagram posted previously is that it is for the USA export models and there are several differences compared with UK models.  However, the coloured diagram is easier to understand than the black and white version in the workshop manual, just do not start looking for your bulb check relay and several other components! The following diagram may help:

Thanks graham, yes i have 12v between black and green but nothing between on the other cables. I am testing between black to l/lg and black to b/lg, i take it that is correct?

And do you think i may have a faulty switch if i am not getting any voltage when doing these tests?

[Pete Lewis]

i would ping the switch apart its probably corroded inside  

as for side lamp flashing you ave a bad earth on that lamp unit so it back feeds via the lower wattage  5w bulb not illuminate the 21w flasher 

Pete

[DVD3500]

How does one get the switch apart without destroying it?

The base with the pipe connections seem to be tightly fixed/glue to the part with the switches...

[chrisbladen]

Ok thanks pete il look into both of these.

Just a thought, with ignition on if i take a feed from a live and connect it to either the red/light green or blue/light green and the motor operates then this will confirm that the motor is operating, right? This way il know i have an issue at the switch?

[DVD3500]

I have successfully jumped the motor using the connectors directly on the motor. Use the wiring diagram as a guide...

[Colin Lindsay]

So it's a duff switch?

[chrisbladen]

5 minutes ago, Colin Lindsay said:

So it's a duff switch?

Seems that way, well either a duff switch or a wiring issue. I just removed connector, wired a ground directly into block and went from live to green and red/green and the motor operated.

Now i think il temporarily wire from switch to block at motor,  this way i'll know for certain if its a wiring issue or an issue with the switch

Am the switches repairable or is it just a case of a new switch

[Pete Lewis]

2 hours ago, DVD3500 said:

get the switch apart without destroying it?

most rockers the top section is clip in place by the pivot lugs etc 

pull push are not so easy as the case is often crimped

Pete

[DVD3500]

HI Pete,

I am not sure I follow you.

Are you saying the electrical part and the part with the bellows are pushed together, or crimped together or twisted on using pivot lugs?

Thanks...

 

[Pete Lewis]

there are two types of switch  not sure when pull push changed to rocker

pull push is not a diy disassembly  and probable would end up mend to destruction some have a metal crimped case some are a forced together plastic two part case 

the later rocker switch does come apart to access the slider and contacts , best done in a poly bag so you dont ping springs all over the workshop floor 

if it looks impossible then it probably is 

Pete

[DVD3500]

Is the "rocker" switch the one you twist with 3 settings: Off, slow, slightly less slow than slow?

 

 

[GrahamB]

I think Pete is referring to a different type of switch to the one that rotates as fitted to early Spitfire 1500.  As the switch also incorporates the washer pump (?) I cannot see how it can be easily dismantled.  They are not cheap so I would remove the switch and check for a connection between 2 and 3 in the first position and 3 and 4 in the second position.  If this proves satisfactory, then it is a wiring fault otherwise a new switch is required.  It might help to repeatedly operate the switch to try to remove oxidation from the internal contacts before testing the switch.

[chrisbladen]

2 hours ago, GrahamB said:

I think Pete is referring to a different type of switch to the one that rotates as fitted to early Spitfire 1500.  As the switch also incorporates the washer pump (?) I cannot see how it can be easily dismantled.  They are not cheap so I would remove the switch and check for a connection between 2 and 3 in the first position and 3 and 4 in the second position.  If this proves satisfactory, then it is a wiring fault otherwise a new switch is required.  It might help to repeatedly operate the switch to try to remove oxidation from the internal contacts before testing the switch.

Thanks graham il give this a try.

When you say check for connection between 2 and 3, and then 3 and 4, do you mean with a multi meter?

[GrahamB]

As you appear to own a multimeter, you can use the buzzer on the continuity check setting to test 2 to 3 (or 3 to 2, it makes no difference) and then 3 to 4 as you operate the switch.  I have found that some times you have to scratch the connector with the multimeter probe to get a good contact.  Alternatively you could attach a known 12 V supply to contact 3 and check for 12 V on 2 in the first switch position and 4 in the second position.

[GrahamB]

While you have the switch out, you should also check the continuity between 1 and 2 with the switch in the Off position as this controls the self parking mode.

[chrisbladen]

4 minutes ago, GrahamB said:

While you have the switch out, you should also check the continuity between 1 and 2 with the switch in the Off position as this controls the self parking mode.

Thank u il giv it a blast. I take it all these tests need to be done with ignition on?

At the risk of sounding a bit thick, what does it mean by self parking mode.

[Pete Lewis]

there is a sweep arm contact in the wiper under the domed cap this takes its supply from the switch and the sweep contact has a gap so when the sweep passes the feed is broken and the wipers stop at the bottom of the screen 

its cut off point is adjusted by loosen the motor cap screws and turn the cap to get the park in the right place 

if the feed is missing or the sweep ring and its copper brush have a fault then the park wont work

Pete

[GrahamB]

I found it very difficult to access the terminals with the switch in position which is why I said test with the switch out of the  dashboard.  If you can test with the switch it position, switch the ignition on and check for 12 V on terminal 3, the other probe of the multimeter being earthed through any unpainted metal such as the head of a screw.  If there is 12 V on 3, move switch to the first position and check that for a reading of 12 V.  Finally move switch to second position and check for 12 V on terminal 4.  Do not use the buzzer on the continuity setting if testing a live circuit.

Off to cook my evening meal but may be back later.

[DVD3500]

I actually tested both my switches yesterday and got no connectivity at all but maybe I wasn't doing the right combination or the contacts were not clean enough...

 

[Pete Lewis]

with the age many simple electrical switches suffer from the nasty green corrosion and grubby contacts 

ans sorry i was not thinking of the rotary switch  ...theres little you can do with them 

if they are going to come apart its fairly obvious as i said if its looking unlikely you will only wreck the switch 

if you can make a small hole a squirt of electrolube or a rocket variant may revive the grot.

Pete