increasing multimeter fuse rating

[Specialist]

Some of the old trucks & machines I've worked on had what we used to fondly call Henry wiring.
Any colour as long as it's Black (Harks back to the old model T ford).
If it still had the markers at each harness junction or end etc, you had a fighting chance.
If not, then hope the local Vicar wasn't passing cause the air would be blue .

Good luck with the job buddy, hope it's an easy one.
A cheap tone tracer often comes in handy.

 

[ruston]

Well I'm hoping it has just blown the supply fuse when the step failed . the mechanic has fitted a new step , but there is no power to the extend/retract switch for either side.
The mechanism is linked to the parking brake so that they will only operate when the brake is on as they slide out from under the sills.
They usually fail because of corrosion though , they are after market wiring seperated from the ECU so it could get involved lol.

 

[Specialist]

Sounds like a bit of an involved setup. Just what you need for a Sunday morning, hope he's got plenty of tea & biccies on the go
Do me a favour & let me know the outcome buddy, always interested in faults on things I wouldn't normally come across.

 

[ruston]

Yes I will.
It also has a system that when the footbrake is on the back doors lock to stop the the unsavoury types doing a runner. It also has an intercom and seperate heater and blower , and cab lighting on the same system. The drivers cab is seperated by a security partition so they are a real pain to work on . Most of the access is under the centre consol or under the seats.
On the plus side there are full workshop facilities , hoists and all the supplies I will need , and a 'bait room ' lol.
Sunday is the best day to do it, less time pressure.

 

[Specialist]

Thanks mate. Certainly sounds shall we say, an interesting set up.

 

[ruston]

Well , to be fair it does not give much bother , there are four of them convertions to wheelchair adapted cabs . The steps seem to be the only stumbling block ( ) as they are under the sills and get all the salt and crap . They have limit switches that suffer badly as does the 'window wiper ' type mechanisim.

 

[Specialist]

Strange how limit switches are always fitted in the worst places, looks like time to get down & dirty mate

 

[ruston]

Yep, going to the bacon sarny van now, then off to crack it lol.

 

[Specialist]

Hi ruston: Just wondering how you got on with the taxi job buddy ?.

 

[ruston]

Well it's sorted. Combination of a few faults that caused the failure .
On the off side the harness from the detachable plug to the unit had been suffering from water ingress to a tube clamped to the top of the unit underneath the sill. This contained two resistors and two caps. One of the resistors ends had corroded and although making contact , was just fortuitous.
On the common signal wire are two caps linked to each microswitch switching wire respectively ; the cap connection was corroded through , this was not making a contact to one switch at all, so that unit was not working at all. An attempt to fix it by replacing the micro switches had failed. The nearside worked , so it was left for another day.

The nearside eventually failed too , this was a combination of a faulty harness plug and a duff micro switch, the switches were replaced (not by me), but it still did not work.
The control unit was getting the signal that the step was deployed and the buzzer could not be stopped sounding with the handbrake on or off , so someone had pulled the two multiplugs out of the unit so the whole system was dead.
No one thought to tell me where the control unit was, or that it had been disconnected. It is in the cab partition hidden behind the drivers seat, with the seat backed right up against it .

 

[Specialist]

Thanks mate, nicely found. Just love when people don't give all the information you need.

 

[ruston]

Well I think it was a bit of embarressment really. To be fair they were never going to find the problem in the harness, the vulcanised tube just looked like part of the harness strengthened where it went from the cover into the motor enclosure. This is located on top of the step under the sill and gets all the elements. The resistors and caps are located in there; not a great design.
They have been sorting them by changing the micro switches , which to be fair is usually all that goes wrong with them, apart from mechanical damage over speed humps and kerbs ect.

 

[Specialist]

Could you possibly fill the tubes with Silicon ?

 

[telectrix]

and end up with this?:

 

[Specialist]

If only tel, she'd kill me. I'd go with a smile though

 

[ruston]

Could you possibly fill the tubes with Silicon ?

Not really , it is rubber vulcanised over a cut away piece of flexible conduit, turns at almost a right angle through an open grommet and into the motor housing.
I wrapped it with self amalgamating tape , but that is just the tip of the iceberg , the covers for the units are not watertight and most are distorted and allow water and grit into the units. We are on the case though , and we are going to modify them as the units are £400 each and there are eight of them

 

[Specialist]

Hi Euston: Sorry mate, missed your reply. Good business for the manufacturer, I suppose they last the guarantee period & after that it's extra sales.
Pretty short sighted to me, but a lot of manufacturers don't care. They know they won't be around for the long game.

 

[Specialist]

Sorry that should have read Hi ruston, I hate predictive text.

 

[ruston]

Yes , micro switches £8 each x2 for each unit +couple of quid for the magnet that rots off the bracket +£8.60 postage. that is the usual problem.
Sign of the times , but to be fair in the three years they have covered some miles and earned their keep.
They do not supply any diagrams or locations of the equipment though , that would have been a great help.

 

[Specialist]

Now if we were in America, they'd be throwing diagrams & manuals at you.