Coleman Presidential II in mobile home outside ac unit coleman also. Switch on front of furnace to change from heat to cool and from auto to continuous. Old, not well maintained!
Pilot light takes a long time of continuous flame to actually light. Blows out occasionally with high winds outside.
Contactor inside the ac unit outside does need replaced because there are black marks "burn marks" present. But, first, the ac "freezes up" often. We turn the t-stat up and switch to continuous for a while to "unfreeze"
This has gotten better since elec. Replaced corroded broken wire buried only 8" underground. (got shocked while digging a flower bed) Elec. Also ran a 4th 100amp wire from pole into home. (only had 3) Next, problems started afterwards.
First, unit wouldn't shut off at all. Then, intermittently the contactor wouldn't engage but if left alone for a day everything was fine. Now, contactor won't engage unless pressed in manually. UPDATE: tURNED switch to cool and, Hooray, it worked! Did cycle a few times also. (this was yesterday) Today[U][U the heat index is 101 degrees and NO AC! PLEASE HELP! Missy P.S. Hvac tech has put me off for 4 or more weeks with only 1 time of contacting me) P.P.S. Fair DIY'er but may need to explain where the part is.

1 more thing: How, if at all, do I replace my t-stat with a programmable one? I only have a red wire and a white wire coming out of the wall. You guessed it, they are marked R and W.
Desperately need cool air, Please Help!