What is the purpose of the HT lead in my cars ignition system?
The HT leads carry the sparks from the ignition system to the spark plugs. There is one lead for each spark plug, and 1 lead from the Ignition coil to the distributor. If a spark plug lead was faulty you would most likely get a misfire and difficult starting. If the coil to distributor lead was faulty the engine may well not run at all. Over time these leads do deteriorate and I would certainly suggest them being changed every 5 years. If you think the leads are faulty it can be interesting to open the bonnet on a dark evening and start the engine up. If you see sparks all over the place then for sure the leads are breaking down and need to be replaced. Replacement is an easy job, buy a set of leads for your vehicle from either a dealer or from a motor factors or Halfords, replace only one lead at a time so you don’t get the order mixed up.
