Why would you add an extra relay to starter?

[Dandy2012]

Hey guys new member first time poster so go easy on me.
I recently changed the starter motor in my vz executive as starting my car was very temperamental. All has gone well and starts fine now. I used a brand new starter from Trump electrical in Thomastown VIC only $90 and works a treat. However whlist fitting the starter I noticed a previous ownée at some stage had added an extra relay to the starter. The feed wire from the original relay had been diverted through a second relay that was cable-tied to my aircon hose. The were powering the relay with the think cable that comes direct from the battery. I know that it doesn't take much power to activate the relay but it is taking it from the starter supply only making matters worse and for the life of me I can't think of a reason anyone would do this! So do you guys have any ideas?

 

[Silverbird]

I'll take a wild guess - maybe a pre-existing problem in the starter circuit. If you return it to standard, you'll soon know.

 

[Dandy2012]

I'll take a wild guess - maybe a pre-existing problem in the starter circuit. If you return it to standard, you'll soon know.

I did return it to normal and it works beautifully. You can hear the power and how fast it cranks. But they didn't ad a completely new relay circuit they simply extended the wiring to another relay so there was actually 2 relays on the starter. The factory and an aditional

 

[strgas]

boost relay added to improve current flow to starter soleniod , old or weak wiring cant pass full current to starter soleniod so auto elecs mechanics will add a simple boost soleniod to take the load off the old orignal wiring ..
sometimes first sign of starter soleniod going weak ..

 

[Dandy2012]

boost relay added to improve current flow to starter soleniod , old or weak wiring cant pass full current to starter soleniod so auto elecs mechanics will add a simple boost soleniod to take the load off the old orignal wiring ..
sometimes first sign of starter soleniod going weak ..

As I explained before they didn't create a new circuit so it was still using all of the old wiring... therefore not providing a boost. If anything making matters worse.

 

[strgas]

so the orignal soleniod wire was disconnect and used to switch the relay only , power from the starter cable direct from the battery with the two remain wires one to ground and one back to the soleniod .
this removes the high load off the orignal starting circuit and puts it thru to the relay now .
replacing the starter motor has resolved the issue due to a new soleniod and lower resistance requiring less current flow .

 

[Dandy2012]

Oh I totally get it now. So the relay was for the solenoid not the starter motor itself which was originally powered directly from the ignition switch. I totally get it. Clever little fix which I will remember if this starter fails but yes having a new starter has made all the difference it's fantastic. I also understand why they needed it it was clear removing the old one that it was second hand from the start. Thanks so much

 

[Silverbird]

Well done to all. Good information here - glad you got your new starter sorted!

 

[Dandy2012]

Agreed very happy with the way my car starts now. Thanks to everyone for the information and input on the matter