SaabCentral Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
3,495 Posts
Discussion Starter #1
Are late-build c900's pre-configured with a wiring harness plug to suit a trailer hitch? I'm looking to get a trailer hitch kit to fit to my 2.1 sedan as it'd be very handy.

The Australian-made Hayman Reese model 723 tow hitch kits are only permitted to haul a maximum 1.5 tonnes with a maximum ball weight of 90 kg.

Also, is there any need to have a seperate 'slave flasher' relay for the indicators so that the trailer indicators are not loading directly off the car's indicator circuits?

Craig.
 

·
Registered
Joined
·
3,495 Posts
Discussion Starter #3
Ok ta re custom-wiring. Any thought on the second part - re a seperate flasher 'slave' relay for the trailer indicator circuits?
 

·
Registered
Joined
·
7,136 Posts
Probably need to do some trial and error or some math... the factory relay flashes at X flashes per second based on Y amp draw in the system.... adding more bulbs will change that rate. Without knowing how many bulbs and what those bulbs are, nobody can tell you whether you need a separate relay.
 

·
Registered
Joined
·
7,088 Posts
Tow my caravan with my C900 no extra flasher, just wired everything to original wiring. (3 different c900's)
 

·
Registered
Joined
·
3,495 Posts
Discussion Starter #6
My 81 turbo which has a trailer harness does it that way. My long-gone red 89 hatchback I think did as well. I'm going to replace the flasher relay with one that can permit the indicator lights in the car to be replaced with LED bulbs anyway.
 

·
Registered
Joined
·
7,136 Posts
The flasher and hazard relay are integrated... not so sure you're going to find any sort of replacement, but please let us know if you do.
 

·
Registered
Joined
·
3,495 Posts
Discussion Starter #8
I know when I had my 89 900i hatchback I replaced the flasher relay with a generic one and had to swap two wires around on the socket then it worked. Did the same to my 81 turbo sedan but that car is stored elsewhere currently. It's just a 3-pin flasher.
 

·
Registered
Joined
·
3,495 Posts
Discussion Starter #9
Righto got Hayman Reese towbar kit all installed and sorted out the minor issues with that (plus issues with mis-supply of some mounting bracket parts), so moving onto wiring. As there is no pre-configured connection into the factory wiring to connect a towbar connector wiring harness I've rigged up a way to mount a flat 7-pin socket (dunno if they're a universal standard or just something specific to oz) on a little bracket and route some 7-core cabling via a hole I made in the rubber block the the rear bumper holds in place over the big round opening in the body to the inside of the car. (*)

The rubber block is otherwise unmodified and still blocks in the big round hole.

* - I considered the idea of a non-fixed-in-place wiring harness that I flop out of the boot when required but I don't really like that idea. :cool:

The most obvious spot to access the wires themselves of the factory wiring seems to be at the LHS tail light since all the wiring to the tail lights seems to run there and a sub-harness for the RHS tail light branches off.

For connectivity, I plan on using 8-pin Deutsch connectors so the harness I make up is removable and if in the future I did fit a trailer brake controller there's provision for it's wire to be linked up.

I don't know yet if I will use Scotchlock type quick-connect joints onto the factory wiring or strip back insulation and re-seal soldered joins... Either way it's going to result in quite a 'nest' of joints.

Craig.
 

·
Registered
Joined
·
3,495 Posts
Discussion Starter #10
Latest news on this is that I have got the outside part of the wiring now sorted using a 7-pin flat socket mounted to a bracket itself mounted to the towbar, and now I'm doing the internal wiring. I tracked down a new oldstock Hella 'Transflash' indicator slave relay unit (still in original packaging) and that seems fairly simple to wire in. I've chosen to not have the trailer wiring 'disconnectable' as it didn't make practical sense. The 'Transflash' relay requires a +12 volt power feed (earth is easy as there's an earth point right at the back of the centre bar that supports the false floor) and wondering where the nearest one is to the back? Power antenna perhaps?

This is the exterior connector:



pic page

And this is the Hella 'transflash' kit with the rear of the original packaging shown:



pic page

I'm thinking that I will permanently mount it here:



pic page

To tap into factory wiring the best place still seems to be near the connector to the left-side tail light board.

Craig.
 
1 - 10 of 10 Posts
Top